Diagnostic apparatus for analyzing arterial pulse waves

ABSTRACT

The present invention relates to a diagnosis apparatus for analyzing arterial pulse waves comprising a database  26  in which is stored data showing the relationship between data representing a pulse wave of a living body and teaching data representing conditions of the living body; and a micro-computer  21  for outputting teaching data corresponding to the pulse wave detected from the living body in the teaching data on the basis of the pulse wave detected from the living body and the stored data inside database  26 . As a result, it becomes possible to perform diagnoses equivalent to a skilled doctor.

CONTINUING APPLICATION DATA

[0001] This application is a divisional of 09/587,050 filed Jun. 2,2000, which is a divisional of 08/302,705 filed Dec. 5, 1994, now U.S.Pat. No. 6,261,235. The contents of each of these prior applications isincorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates to a diagnostic apparatus forperforming diagnostics based on parameters and data obtained from thepulse waves generated by a living body, and to a pulse wave analyzingapparatus for generating the parameters and data representing the pulsewaves of the living body.

[0004] 2. Background Art

[0005] The traditional medicine, for example, the Chinese medicine haslong practiced pulse taking at three locations (Chun, Guan, and Chi) onan arm along the radial artery. Also, there is a method for takingpulses automatically with three piezoelectric elements which arerespectively pressed at the three points. (Japanese Patent Application(JPA), Second Publication, S57-52054). Further, to equalize the fingerpressure at the piezoelectric elements, it is known that air pressure isused to press down the piezoelectric elements (JPA, First Publication,H04-9139).

[0006] On the other hand, a technique called Ayurveda has been known intraditional Indian medicine from ancient times. This method will beexplained with reference to FIGS. 3A and 3B.

[0007] An examiner places his fingers lightly on three locations alongthe radial artery of an examinee. The three locations shown in FIG. 3Aare referred to as Vata (V), Pitta (P) and Kapha (K), and correspondroughly to the three locations in the Chinese Medicine known as theChun, Guan and Chi. The examiner places his second finger on Vata (V),his third finger on Pitta (P) and his fourth finger on Kapha (K), andchecks the pulsing motions at the variant depths.

[0008] Next, the examiner performs a diagnostic analysis of the healthcondition of the examinee based on the sections and strength of theexaminee's pulse felt at the four points on his one finger asillustrated in FIG. 3B. It follows, therefore, that with the threefingers, he can perform the diagnostic analysis based on a total oftwelve points.

[0009] Such wrist pulse method and the Ayurveda technique are said toprovide excellent diagnostics, but because these techniques aredependent on the accumulated experience and the sensation felt by theExaminer, the techniques are difficult to be fully mastered. Inparticular, diagnosis by the Ayurveda method is restricted to those withextreme sensitivity at the finger tip, which can number as little as onein a thousand, or one in several thousand people. Moreover, even forthose with sensitive touch, unless they have had many years of training,they cannot make an accurate diagnosis.

[0010] As described above, the pulse waves are useful index of theconditions of a living body, and potentially form an excellent basis fora diagnostic technique. If it is possible to derive information relatedto the conditions of the living body from the pulse waves, and toperform objective and accurate diagnostics based on such information, itwould signify a great leap in the field of remedial medicine.

[0011] The present invention was made in view of the background of thediagnostics technology presented above, and some of the objectives ofthe present invention are to present:

[0012] (1) A diagnostic apparatus for performing diagnosis of theconditions of an examinee based on the pulse waves obtained from theexaminee in a manner similar to expert medical person.

[0013] (2) A pulse wave analysis apparatus for analyzing and acquiringdata which not only reflect the conditions of the examinee but enableobjective diagnosis to be performed.

[0014] (3) A diagnostic apparatus for performing objective diagnosis ofthe conditions of the examinee based on pulse waves obtained from theexaminee.

SUMMARY OF THE INVENTION

[0015] To achieve these objectives, the diagnostic apparatus of thepresent invention comprises: an analysis section for generating waveformparameters from the information, obtained from an examinee, representingthe conditions of the examinee; and a diagnostic section for performingdiagnosis of the conditions of the examinee based on the waveformparameters.

[0016] More specifically, the analysis section of the present inventiongenerates the following waveform parameters by analyzing the pulse wavesobtained from the examinee:

[0017] (1) values of the elements of an electrical circuit model (lumpedfour parameter circuit model) which simulates the arterial system of aliving body from a proximal section to a distal section;

[0018] (2) distortion factors in the waveforms in comparison toreference waveforms obtained from a plurality of living bodies;

[0019] (3) peak points (inflection points) in the waveforms and/or theirgeneration timing; and

[0020] (4) a frequency spectrum of sequential pulse wave data.

[0021] The diagnostic items which can be analyzed by the apparatus ofthe present invention are illustrated by way of various embodiments, anddisclosed in the claims of the present invention.

[0022] Other objects and attainments together with a fullerunderstanding of the invention will become apparent and appreciated byreferring to the following description and claims taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a block diagram of a diagnosis apparatus according to afirst embodiment of the present invention;

[0024]FIG. 2 is a plan view showing the essential parts of a pulse wavesensor used in the embodiment;

[0025]FIG. 3A is a diagram illustrating the three pulse taking locationon the arm of an examinee in Ayurveda technique;

[0026]FIG. 3B is a diagram illustrating the four points on theexaminer's finger in the Ayurveda technique;

[0027]FIG. 4A to FIG. 4C are graphs showing examples of detected pulsewaves;

[0028]FIG. 5A to FIG. 5C are graphs showing examples of detected pulisewaves;

[0029]FIG. 6 is a graph showing examples of detected pulse waves;

[0030]FIG. 7 is a graph showing examples of detected pulse waves;

[0031]FIG. 8 is a graph showing examples of detected pulse waves;

[0032]FIG. 9 is a graph showing examples of detected pulse waves;

[0033]FIG. 10 is a block diagram to show a pulse wave analysis apparatusto compute dynamic parameters of the circulatory system based on theconcept of a second embodiment of the present invention;

[0034]FIG. 11 is a schematic illustration of using the pulse wavedetection device and the stroke volume determination device;

[0035]FIG. 12 is a schematic circuit diagram showing a lumped fourparameter circuit model to simulate the arterial system of a human body;

[0036]FIG. 13 is an illustration of the blood pressure waveforms at theaorta ascendens and the blood pressure waveforms in the left ventricleof the heart;

[0037]FIG. 14 is an illustration of the electrical signal waveformmodeling the blood pressure waveform at the above aorta ascendens;

[0038]FIG. 15 is a flowchart showing the routine for the operation ofthe second embodiment;

[0039]FIG. 16 is a flowchart showing the routine for the operation ofthe embodiment;

[0040]FIG. 17 is a flowchart showing the routine for the operation ofthe embodiment;

[0041]FIG. 18 is a flowchart showing the routine for the operation ofthe embodiment;

[0042]FIG. 19 is a flowchart showing the routine for the operation ofthe embodiment;

[0043]FIG. 20 is an example waveform showing the radial arterialwaveform obtained by an averaging process;

[0044]FIG. 21 is an illustration of the overlap display of a radialarterial waveform obtained by the averaging process and a radialarterial waveform obtained by the computation processing;

[0045]FIG. 22 is an example of the radial arterial waveform obtained bythe averaging process;

[0046]FIG. 23 is an illustration of the other electrical signal waveformmodeling the blood pressure waveform at the above aorta ascendens;

[0047]FIG. 24 is a perspective of a pulse wave sensor;

[0048]FIG. 25 is a block diagram of the pulse wave detection device;

[0049]FIG. 26 is a circuit diagram representing the expansion of thelumped four parameter circuit model for the arterial system;

[0050]FIG. 27 is a schematic block diagram to show of a diagnosticapparatus based on the shape of pulse Waveforms, and based on theconcept of a third embodiment of the present invention;

[0051]FIG. 28 is an illustration to explain a method of pulse waveexamination;

[0052]FIG. 29 is a schematic block diagram to show the configuration ofanother diagnostic apparatus;

[0053]FIG. 30 is a schematic block diagram to show the configuration ofthe other diagnostic apparatus;

[0054]FIG. 31A is a typical waveform of Ping mai type;

[0055]FIG. 31B is a typical waveform of Hua mai type;

[0056]FIG. 31C is a typical waveform of Xuan mai type;

[0057]FIG. 32 is a bar graph to show the relationship between thedistortion factor d and the three types of pulse waveform;

[0058]FIG. 33 is a graph to show the relationship between the distortionfactor d and the proximal section resistance Rc;

[0059]FIG. 34 is a graph to show the relationship between the distortionfactor d and the distal section blood flow resistance Rp;

[0060]FIG. 35 is a graph to show the relationship between the distortionfactor d and the blood flow momentum L;

[0061]FIG. 36 is a graph to show the relationship between the distortionfactor d and the vascular compliance C;

[0062]FIG. 37 is a bar graph to show the relationship between theproximal section blood flow resistance Rc and the three types ofwaveforms;

[0063]FIG. 38 is a bar graph to show the relationship between the distalsection blood flow resistance Rp and the three types of waveforms;

[0064]FIG. 39 is a bar graph to show the relationship between the bloodflow momentum L and the three types of waveforms;

[0065]FIG. 40 is a bar graph to show the relationship between thecompliance C and the three types of waveforms;

[0066]FIG. 41 is a block diagram to show another example of calculatingthe distortion factor d;

[0067]FIG. 42 is an example of pulse waves used in stress levelevaluation according to an fourth embodiment of the present invention;

[0068]FIG. 43 illustrates a psychosomatic fatigue level diagnosticquestionnaire used in the embodiment;

[0069]FIG. 44 is a block diagram showing a construction of a firstvariation of a stress level evaluation apparatus in accordance with thefourth embodiment of the invention;

[0070]FIG. 45 is a block diagram showing a construction of a secondvariation of a stress level evaluation apparatus;

[0071]FIG. 46 is a block diagram showing a structural example of theparameter sampling unit (or the waveform sampling memory) of the secondvariation;

[0072]FIG. 47 is a diagram illustrating the stored contents of the peakinformation memory of the variation;

[0073]FIG. 48 is a diagram illustrating the radial arterial pulsewaveform recorded in the waveform memory of the variation;

[0074]FIG. 49 is a display of stress level evaluated by a thirdvariation of a stress level evaluation apparatus;

[0075]FIG. 50 is a block diagram showing a structure of a pulse waveanalyzing apparatus according to a fifth embodiment of the presentinvention;

[0076]FIG. 51 is a block diagram showing the structure of frequencyanalyzing unit in the embodiment;

[0077]FIG. 52 is a diagram illustrating waveform transfer timing from awaveform sampling memory to a frequency analyzing unit;

[0078]FIG. 53 is a timing chart showing an operation inside the waveformsampling memory;

[0079]FIG. 54 is a diagram explaining an operation of a high speedplayback unit;

[0080]FIG. 55 is a diagram explaining the operation of the high speedplayback unit; and

[0081]FIG. 56 is a diagram explaining the operation of the high speedplayback, and a sine wave generator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] Best Mode for Carrying Out the Invention

[0083] Preferred embodiments of the present invention will be explainedwith reference to the drawings. All of these embodiments are based onthe results of analysis and diagnosis performed on actual pulse wavesdetected from actual examinees.

[0084] To facilitate understanding, the embodiments are presented inseparate Chapters 1 to 5 so that those skilled in the art may be able toduplicate the embodiments.

[0085] In Chapter 1, an expert system is presented to perform diagnosisbased on most easily recognizable waveforms so that the principle of thepresent invention can be understood by those skilled in the art. Toperform such a diagnosis, it is necessary that the waveforms arecorrelated to conditions of an examinee, and additionally thoseparameters must be truly reflective of the conditions of the examinee.

[0086] In Chapters 2 and 3, circulatory dynamic parameters are chosen torepresent the parameters representing the conditions of an examinee. Amethod for obtaining such hemodynamic parameters are illustrated with anembodiment, as well as an embodiment for a diagnostic apparatus forperforming diagnosis based on such parameters.

[0087] In Chapter 4, an embodiment of a diagnostic apparatus ispresented to obtain relevant information related to the condition of anexaminee, and to perform diagnosis based on such information. Theexplanations provided include specific steps so that those skilled inthe art may be able to construct such diagnostic apparatuses inaccordance with the present invention. The disclosures of Chapter 4 arehelpful to those skilled in the art to construct devices other than thepsychosomatic stress level analysis apparatus presented in theembodiment.

[0088] In Chapter 5, an improved pulse wave analysis apparatus ispresented to further improve the performance of the apparatusespresented in the foregoing embodiments.

[0089] Chapter 1: Diagnostic Apparatus

[0090] First, a first embodiment of the diagnostic apparatus accordingto the present invention will be explained. This diagnostic apparatushas a pre-recorded memory which relates the pulse wave data to theconditions of a living body, and performs comparative analysis toidentify the detected waveform of an examinee with the stored waveformsin the memory.

[0091] Chapter 1 is devoted exclusively to the first embodiment of thepresent invention.

[0092] Chapter 1-1: Structure of the Embodiment FIG. 2 shows a plan viewof a pulse wave sensor used in the embodiment.

[0093] In FIG. 2, numerals 81-84 indicate a set of band shaped straingages which are arranged in parallel in the longitudinal direction on afinger portion of a rubber glove 5. The thickness of the rubber glove 5is approximately 200 μm. Standard gauge type adhesive is used to fixedlyattach the strain gages 81-84 to the rubber glove 5.

[0094] The details of the strain gages 81-84 are as follows:

[0095] Each of the strain gages 81-84 is a thin gauge with a gaugefactor of 2.1; resistance of 120 ohms; a width (D) of 2.8 mm; a length(L) of 9.4 mm; and a thickness of 15 μm. The overall width M of thestrain gages 81-84 corresponds to the contact width of the finger of theexaminer when the finger is gently pressed on an arm of the examinee,and is set at approximately 12 mm. Accordingly, the distances (S)between the gauges 81-84 is approximately 0.27 mm.

[0096] The strain gauges 81-84 correspond to the measuring points 1-4 asshown in FIG. 3B, and are used to measure the pulsing motion at therespective Ayurveda shown in FIG. 3A.

[0097] The construction of the diagnostic apparatus using the straingages 81-84 will be explained with reference to FIG. 1.

[0098] In the figure, a strain gage 81 and a resistor 12 are connectedin series, with a predetermined DC voltage E applied by a voltage source11. Accordingly, an AC voltage V_(i) corresponding to the resistanceratio, is generated across the ends of the strain gage 81. The numeral13 indicates a DC cut-off filter which removes the DC component of theAC voltage V_(i.)

[0099] The output signal from the DC cut-off filter 13 is amplified byan amplifier 14, and outputted by way of a low pass filter 15 which hasa cut-off frequency of 20 Hz. FIG. 2 shows only the circuitcorresponding to the strain gage 81. Similar circuits are respectivelyprovided for the other strain gages 82-84.

[0100] Subsequently, the output voltage Vo from the low pass filter 15,is converted into a digital signal by an A/D converter 20, and thensupplied to a micro-computer 21. The micro-computer 21 comprises a CPU24, a ROM 22, a RAM 23, and a display device DP. It also has a database26 as an external memory. A program specifying the operation of the CPU24, is stored in the ROM 22, while a working area is set in the RAM 23.The numeral 25 indicates an input device comprising a keyboard or thelike, whereby various commands and messages can be input to the CPU 24.The numeral 30 indicates a recorder, which prints out waveform datasupplied from the CPU 24, on a specified sheet.

[0101] Chapter 1-2: Operation of the Embodiment

[0102] There are two operative modes of the first embodiment; thelearning mode and the diagnostic mode. The explanations for theoperation of the first embodiment are divided into those two modes.

[0103] Chapter 1-2-1: Learning Mode

[0104] The learning mode is used to store the relationship between theparameters representing the pulse waves (waveform parameters) obtainedfrom the examinee and the data representing the conditions of theexaminee (i.e., diagnosis results).

[0105] With the above construction, the examiner wears the rubber glove5 on one hand, and presses the second finger on the Vata (V), the thirdfinger on the Pitta (P), and the fourth finger on the Kapha (K), of theexaminee.

[0106] In this condition, respective voltages Vi are outputted from atotal of 12 strain gages, corresponding to the pulsing motion of theexaminee. The direct current components of these voltages Vi arefiltered out in the corresponding DC cut-off filters 13, and aresupplied to the micro-computer 21 by way of the respective correspondingamplifiers 14, low pass filters 15, and A/D converters 20. The waveformssupplied in this way are analyzed in the micro-computer 21, andparameters indicating the characteristics are computed. These parametersare then stored temporarily in the RAM.

[0107] In the present embodiment, the amplitudes of the respectivefrequency components constituting the pulse waves are used as thecharacterizing parameters. That is to say, a frequency spectrum analysisby Fast Fourier Transform is carried out for the respective waveforms(the program for the Fast Fourier Transform is pre-stored in ROM 22 orRAM 23), and the amplitudes of the various frequencies are used asparameters. Further, as will be explained subsequent to Chapter 2, thepresent invention may utilize various other parameters representing thepulse waves.

[0108] The examiner then inputs diagnosis results(as teaching data)corresponding to the computed parameters from the input unit 25. Thediagnosis results in this case are those from the sense of the fingertouch, and those from observation of the waveform displayed on thedisplay device, or both of these. Additionally, a completely differentmethod of diagnosis such as a Western medical opinion may also be used.The input may also include words directly indicating the name of anillness and symptoms can be inputted from the input unit 25. The inputdata may also be corresponding codes.

[0109] When the diagnosis results from the examiner are inputted, theCPU 24 stores these in the database 26 matched with the parametersstored temporarily in the RAM 23.

[0110] Next, the learning mode will be explained for each actualsymptoms of an illness.

[0111] (1) Chronic nasal inflammation

[0112] In this example, the patient was a 28 year-old-male, diagnosed byWestern medical opinion to have chronic nasal inflammation.

[0113] The pulse waves measured from the patient were recorded by therecorder 30. The results are shown in FIGS. 4A-4C. Here the verticalscale in FIG. 4A is 2 times that in FIGS. 4B and 4C. This is done forconvenience to keep the waveform on the scale. Accordingly, theamplitude of Udana Vata (V) waveform is large compared to the otherwaveforms. Furthermore, from the observation of the measured results ofthe Vata (V) in FIG. 4 (A), it can be seen that the waveform amplitudesfor the first and second points are much larger compared to those forthe third and fourth points.

[0114] Meanwhile, the micro-computer 21 performs a frequency spectrumanalysis by Fast Fourier Transform on the respective waveforms, and theresults are stored in the RAM 23 as parameters.

[0115] For the pulse wave characteristics shown in FIGS. 4, the Ayurvedatechnique gives a diagnostic opinion of a nasal pharynx disorder. Withthe appearance of such pulse waves there is a statistically highprobability of a disorder in the nose, throat or bronchial tube. Thishas been reported in “Visualization of Quantitative Analysis of thePulse Diagnosis in AYURVEDA: K. Kodama, H. Kasahara, The proceeding ofthe 4th world congress holistic approach-health for all in Bangalore,India 1991”.

[0116] From the observation of the output results from the recorder 30,and the waveform shown on the screen of the display DP, and also from anAyurveda diagnosis by sense of touch, or on the basis of a Westernmedical opinion, the examiner inputs an opinion for the diagnosed result(chronic nasal inflammation), or a code indicating this opinion, fromthe input unit 25 into the diagnostic apparatus.

[0117] Subsequently, the CPU 24 matches the diagnosed input result withthe parameters temporarily stored in the RAM 23, and stores them both inthe database 26.

[0118] (2) Liver Disorder Example (i) In this example the patient was a28-year-old male with a liver disorder (GTO “42”, GPT “63”).

[0119] The examiner's pulse wave measurement results are shown in FIGS.5A -5C. The scales in these FIGS. are the same. From these results itcan be seen that the amplitude of the waveforms for the Ranjaka Pitta(P) of the third finger are large compared to those for the otherfingers. A magnified view of FIG. 5B is shown in FIG. 6. From FIG. 6 itcan be seen that the amplitude for the second point is greater than thatfor the other points.

[0120] The micro-computer 21 performs a frequency spectrum analysis byFast Fourier Transform on the respective waveforms in similar manner tothe above case (1), and the results are stored in the RAM 23 asparameters.

[0121] Incidentally, the Ayurveda diagnosis indicated a liver disorderor the stomach/intestine problem.

[0122] Here the examiner in a similar manner to the above mentionedcase, from an Ayurveda opinion by sense of touch, or on the basis of aWestern medical opinion, inputs an opinion for the diagnosed result(liver disorder), or a code indicating this disorder, from the inputunit 25 into the diagnostic apparatus.

[0123] Subsequently, the CPU 24 matches the inputted diagnosis resultwith the parameters temporarily stored in the RAM 23, and stores them inthe database 26.

[0124] (3) Liver Disorder Example (ii)

[0125] Next example is a diagnosis for a different liver disorder. Thepatient was a 24-year-old male with a liver disorder (GTO “36”, GPT“52”).

[0126] With this patient also, the amplitude of the waveform in theRanjaka Pitta (P) was larger than the amplitude for the other fingers.The waveform measurement results for this Pitta (P) are shown in FIG. 7.In FIG. 7 it can be seen that the amplitude for the second point isgreater than that for the other points. Accordingly, with this liverdisorder example also, similar results to those of the before mentionedliver disorder example (i) were obtained.

[0127] In this case also parameter computations by the computer 24, andinput of the results by the examiner are done in a similar manner to theabove case. However, since the waveforms of FIG. 5 and FIG. 7 wereslightly different, the parameters were slightly different to the caseof the liver disorder (i). Even though the diagnostic results are thesame, because a certain degree of variation appears in the possibleparameter values, the reliability of the limits can be improved byaccumulating many clinical examples.

[0128] (4) Heart Disorder (i)

[0129] In this example, the patient was a 26-year-old male havingirregular pulses which appeared several times an hour due to an outercontracting ventricle of the heart.

[0130] With the waveform measurement results of the patient, theamplitude of the waveform for the Sadhaka Pitta (P) of the third fingerwas larger than these for the other fingers. The waveform measurementresults for the Sadhaka Pitta (P) are shown in FIG. 8. As is clear fromFIG. 8, the amplitude for the third point is greater than those for theother points.

[0131] Incidentally, the Ayurveda diagnosis indicated a disorder of theheart for the above illness example. Accordingly, in this diagnosisexample also, the diagnosis results from the Ayurveda or from Westernmedical opinion were inputted for the parameters calculated by the CPU24, and both were matched and stored in the database 26 so that thesymptoms with respect to the pulse waves could be learnt.

[0132] (5) Heart Disorder (ii)

[0133] To confirm the reproducibility of the heart disorder example (i),a diagnosis was made for a different heart disorder example. The patientwas a 38-year-old male having irregular pulses which appeared severaltimes an hour due to an outer contracting ventricle of the heart.

[0134] With this patient also, the amplitude of the waveform for theSadhaka Pitta (P) of the third finger was larger than those for theother fingers. The waveform measurement results for the Sadhaka Pitta(P) are shown in FIG. 9. As is clear from FIG. 9, the amplitude for thethird point is greater than those for the other points.

[0135] In this case also parameter computations by the computer 24 andinput of the results by the examiner are made in a similar manner to theabove cases, and matched and stored in the database 26.

[0136] Chapter 1-2-2: Diagnosis Mode

[0137] Next, the diagnostic mode will be explained. The diagnostic modeperforms: detection of pulse waves from an examinee; computation of theparameters representing the pulse waves; and diagnosis by reading outapplicable diagnostic results from the database 26.

[0138] The examiner operates the input unit 25 to indicate the diagnosismode for input to the CPU 24. Then in a similar manner to that for thelearning mode, he puts one hand into the rubber glove 5, and his secondfinger presses the examinee at Vata (V); his third finger at Pitta (P);and his fourth finger at Kappa (K).

[0139] As a result, respective voltages Vi are output from the straingages of the respective fingers, and supplied to the microcomputer 21 byway of the DC cut-off filter 13, amplifier 14, low pass filter 15 andA/D converter 20. The micro-computer 21 then calculates parameters toexpress the characteristics of the supplied waveforms, and temporarilystores these in the RAM 23. The CPU 24 then searches in the database 26,for a parameter equal to the parameter temporarily stored in the RAM 23,or the closest parameter to that parameter, reads the diagnosis resultmatched with that parameter, and displays this on the display device DP.In this case, if there is no equivalent parameter, the diagnosis resultscorresponding to the closest parameter are displayed, then that fact isalso displayed at the same time. Such a message is pre-stored in the ROMas character information, and appropriately displayed.

[0140] With the display device DP as described above, diagnosis results(as teaching data) such as chronic nasal inflammation, liver disorder,heart abnormality/disorder are displayed. Accordingly, the examiner canmake a diagnosis for that patient based on the displayed results.

[0141] Here, the embodiment offers an advantage that if teaching datacompiled by expert Ayurveda practitioner had been pre-loaded in thediagnostic memory provided in the learning mode, even a beginner in theAyurveda technique would be able to perform a diagnosis at the expertlevel.

[0142] Chapter 1-3: Variation of the First Embodiment

[0143] The first embodiment is not limited to the above diagnosticapparatus. For example, a number of variations such as given below arealso possible.

[0144] Variation (i)

[0145] In the first embodiment, the frequency spectrum by FFT were usedas waveform parameters. However, instead of this, each value of theelements of a lumped four parameter circuit model simulating thearterial system may be used. The electrical model will be describedbelow.

[0146] Variation (ii)

[0147] Waveform spectrum obtained by discrete FFT, or waveform spectrumobtained by the so-called maximum entropy method technique may be usedfor the parameter.

[0148] Variation (iii)

[0149] In the above embodiment, the radial arterial pulse waves wereused. However, it is possible to utilize parameters for brain waves orfinger tip pulse waves. Moreover, parameters for the accelerating waveof the finger tip pulse wave may be utilized. The main point is that thepresent invention is applicable provided there is some wave motion whichreflects the condition of the living body. The living body to bemeasured is not limited to human beings but may be other types ofanimals.

[0150] Variation (iv)

[0151] In the traditional medicine, Ayurveda for example, a large amountof diagnostic data has already been accumulated. Accordingly, if thisdata can be used directly and quickly in a clinical manner, then thereis ease when it is better to adjust the number of measuring points tothose of the traditional medicine. Hence, it is permissible to have lessthan four strain gages provided there is more than one. For example, itis known that the traditional medicine of Tibet considers twomeasurement points on one finger. Accordingly, in carrying out thediagnosis based on this traditional medicine, two gauges wouldsufficient.

[0152] Variation (v)

[0153] In the circuit shown in FIG. 1, the pulse wave is detected bydirectly measuring the voltage Vi across the terminals of the straingage 81. However a bridge circuit with the strain gage 81 at one sidecan be constructed, and the pulse waves are detected by measuring thevoltage across the opposite corners of the bridge circuit. Byconstructing a bridge circuit with the strain gage and three thin filmresistors having the same temperature resistance coefficient as thestrain gage 81 adhered to the rubber glove 5, then a temperature driftdue for example to the body temperature can be compensated for, and thesensitivity can be improved.

[0154] Variation (vi)

[0155] In the circuit shown in FIG. 1, a current is suppliedcontinuously to the strain gage 81. However the current supply to thestrain gage 81 may be intermittent. That is to say, with the circuit inFIG. 1, since the portion of the frequency component of the voltage Videtected finally as pulse waves only has frequency components below 20Hz, therefore even with the results sampled at a frequency of 40 Hz,adequate waveform reproduction is possible. Hence the current suppliedto the strain gage 81 can be intermittent, enabling a reduction in powerconsumption, which is beneficial, particularly with portable equipment.

[0156] Variation (vii)

[0157] In the first embodiment, the parameter inside the database 26matching the calculated parameter in the diagnostic mode is retrieved.However instead of this, respective threshold values can be set for theupper and lower limits of the respective parameters inside the database26. When in the diagnosis mode, if the calculated parameters fall withinthis range, they can be considered as the relevant parameters inside thedatabase 26, and that diagnosis result may be outputted. Moreover, withthe data inside the database 26, this is updated when new diagnosisresults are inputted for the same parameter. However, if a parameter ofa close value is newly inputted, the above threshold value can beupdated.

[0158] Variation (viii)

[0159] In the above embodiment, the pulse wave parameter is calculated,stored and a comparison is made. However, when there is no problem withincreasing the memory capacity or processing time, the waveformsthemselves can be stored and compared.

[0160] Variation (ix)

[0161] It is also possible to display the therapeutic procedurecorresponding to the symptoms of the patient together with or instead ofthe diagnosis results. The therapeutic procedure may be outputted as theteaching data in the first embodiment. In the learning mode, diagnosisresults together with the therapeutics (or the therapeutics instead ofthe diagnosis results), can be inputted easily.

[0162] In the above, the configuration of the basic diagnostic apparatushas been explained. In the following Chapters 2 through to 5, parametersrepresenting the pulse waves will be explained together with the methodof generating such parameters.

[0163] Chapter 2: Pulse Wave Analyzer for Computing Parameters of theCirculatory System

[0164] In the modern medicine, the most common procedure in theexamination process of the cardiovascular system of a human body, is tomeasure the blood pressure and the heart beat rate. However, to performmore detailed examination, other circulatory dynamic parameters such asthe vascular resistance and compliance must also be examined.

[0165] Conventionally, to measure such circulatory dynamic parameters,it is necessary to determine the pressure waveforms and the blood flowrate at the aorta ascendens and at an incision site. The measurementmethod involves either directly by an insertion of a catheter in anartery, or indirectly by ultrasonic measurement.

[0166] However, according to the catheter method, there is a problemthat a large invasive equipment is required. The ultrasonic techniquecan measure the blood flow non-invasively, but the technique requiresexpert operator, and the apparatus is also large.

[0167] To solve these problems, the present inventors therefore deviseda pulse wave analysis apparatus based on an electrical simulationcircuitry to non-invasively follow the hemodynamics of a living bodywith the use of circulatory dynamic parameters.

[0168] More specifically, the pulse wave analysis apparatus operates by:simulating the arterial system from a proximal section to a distalsection with an electrical circuit (hereinbelow referred to as theelectrical model); entering electrical signals representing the pressurewaveforms at the proximal section into the circuit; iterating the valuesof the elements of the circuit so as to duplicate the actual pressurewaveforms detected from the distal section of the examinee; andoutputting the computed results corresponding to each of the circulatorydynamic parameters.

[0169] In this case, it is obvious that the computed parameters may beused as the waveform parameters in the first embodiment.

[0170] In this pulse wave analysis apparatus, the radial arterialpressure waveforms are used as the waveforms to be analyzed in thedistal section of the living body, and the aorta ascendens pressurewaveforms are used as the waveforms to be analyzed in the proximalsection of the living body.

[0171] Also in this embodiment, the basic assumption is that thepressure waveforms at the aorta ascendens are nearly constant and arenot much affected by the conditions of the living body, and it is mainlythe performance of the arterial system which is affected by theconditions of the living body. This assumption has been clinicallyverified by the inventors.

[0172] In the following, a pulse wave analysis apparatus according to asecond embodiment will be explained.

[0173] Chapter 2-1: Structure of the Embodiment

[0174]FIG. 10 shows a block diagram of the pulse wave analysis apparatusin accordance with the second embodiment of the invention.

[0175] This embodiment computes the circulatory dynamic function of anexaminee based on information obtained from evaluation of thecirculatory dynamic parameters of a human body with a non-invasivesensor. The actual details of the circulatory dynamic parameters will beexplained later.

[0176] In FIG. 10, the reference numeral 201 refers to a pulse wavedetection apparatus, 202 is a stroke volume determination device. Thepulse wave detection apparatus 201 determines the radial artery waveformvia the pulse wave sensor S1 worn on the examiner's hand (or on thewrist of an examinee), as shown in FIG. 11, and also determines theblood pressure of the examinee via a cuff belt S2 worn on the upper armsection of the examinee. The waveform of the radial artery is correctedby the blood pressure, and the corrected waveform of the radial arteryis outputted as electrical analogue signal.

[0177] The analogue signal outputted from the pulse wave detectiondevice 201 is inputted into an A/D converter 203, and is converted intodigital signals for every sampling cycle. Also, the stroke volumedetermination device 202 is connected to the cuff belt S2, as shown inFIG. 11, and determines the volume of blood circulated for one pulsation(beat) via the cuff belt S2, and outputs the results (digital signals)as the stroke volume per pulsation. This measurement can be provided bythe so-called Contraction Surface Area method.

[0178] Here, the details of the pulse wave sensor S1 will be explainedwith reference to FIG. 24.

[0179] In this figure, the reference numeral 251 refers to a surgicalrubber glove, which is provided with strain gages 252-254 at the fingerpad side of the first joint of the index, third and fourth fingers. Thestrain gages 252-254 are thin gages, and have a gage factor (170), aresistance (2 k ohm), a width (0.5 mm) and a length (4 mm). Each of thestrain gages 252-254 is fixed on a flexible thin base, and is attachedto the rubber glove 251 with thin the base.

[0180] Next, the pulse wave detection device 201 is explained withreference to FIG. 25.

[0181] In the figure, the reference numeral 268 refers to a known bloodpressure meter, and measures and outputs the blood pressure valuethrough the cuff belt S2. The numeral 261 is a constant current source,and supplies a constant current to the strain gage 252. The ends of thestrain gage 252 generate a voltage V_(g) to correspond to the degree ofphysical strain. The voltage V_(g) is amplified through a direct current(DC) amplifier 262, and is supplied to the DC cut-off circuit 263 and tothe averaging circuit 265. The output voltage generated by the DCamplifier 262 can be expressed as (V_(o)+V_(d)+ΔV). Here V_(o) is thevoltage generated when the examiner wears the glove 251, V_(d) is thevoltage generated when the examiner's finger is pressed against the armof the examinee. The voltage ΔV is an alternating current (AC) voltagegenerated by the pulse pressure of the examinee.

[0182] The DC cut-off circuit 263 eliminates the first two DC componentsfrom the voltages, V_(o), V_(d) and ΔV, and outputs the AC voltage ΔV,i.e. the pulse wave signal. The pulse wave signal is supplied, afterremoving the noise, to the micro-computer 204 via a low pass filter 264with the cut-off frequency of 20 Hz via the A/D converter 203 (See FIG.10).

[0183] On the other hand, the averaging circuit 265 detects the maximumvalue of (V_(o)+V_(d)+ΔV), and taking a cycle to be to the period of thenext generation of the maximum value of (V_(o)+V_(d)+ΔV), obtains anaverage value of (V_(o)+V_(d)+ΔV). This operation eliminates the ACcomponent ΔV, and the DC component (V_(o)+V_(d)) is outputted. Thereference numeral 266 is a level memory circuit, and when a switch 266 ais pressed down, memorizes the output voltage value at that time of theaveraging circuit 265, and outputs the voltage at the memorized levelperiodically. The numeral 267 is a decrementor, and subtracts the outputvoltage of the level memory circuit 266 from the output voltage of theaveraging circuit 265, and outputs the decremented value.

[0184] In FIG. 25, when the examiner wears the glove 251, the DCamplifier 262 output a voltage V_(o). When the switch 266 a is pressedin this condition, the voltage V_(o) is memorized in the level memorycircuit 266. Next, the examiner presses the finger while wearing theglove 251 on the arm of the examinee, the averaging circuit 265generates a voltage (V_(o)+V_(d)), and a voltage Vd corresponding to thefinger pressure of the finger is outputted via the decrementor 267. Atthe same time, the voltage ΔV corresponding to the pulse wave isoutputted successively through the DC cut-off circuit 263, and the lowpass filter 264. Further, the examiner can carry out his own examinationbased on finger feeling using the strain gages 252-254 disposed on thethin rubber glove 251. The above circuit components 261-267 are providedto work with the strain gages 252, but similar circuit components areprovided for the strain gages 253, 254.

[0185] The micro-computer 204 performs the following steps in accordancewith the commands inputted through the keyboard 205.

[0186] (1) Reading of the pulse waves by storing the sequenced digitalsignal of the radial artery pulses obtained through the A/D converter203 in an internal waveform memory.

[0187] (2) Averaging of the pulses taken at the three locations (Chun,Guan, Chi) and taken into the internal memory, and obtaining acorresponding radial artery pulse waveform.

[0188] (3) Taking in of pulsing volume data.

[0189] (4) Obtaining an equation to correspond with the above one pulse,and based on this equation, and calculating each parameter to correspondwith an electrical model of the arterial system of the examinee.

[0190] (5) Outputting the parameters obtained by parameter computationas circulatory dynamic parameter from an output device (not shown; forexample, printer, display device etc.)

[0191] The details of these processing steps will be explained under theexplanation section for the operation.

[0192] Chapter 2-1-1: With Respect to the Electrical Model Utilized inThis Embodiment

[0193] (1) Lumped Four Parameter Circuit Model

[0194] In this embodiment, a four-element lumped circuit shown in FIG.12 is used for an electrical model simulating the circulatory arterialsystem of a human body. The elements of the electrical model arecorresponding to four circulatory dynamic parameters:

[0195] a blood flow momentum at the proximal section in the arterialsystem;

[0196] a vascular resistance due to blood flow at the proximal sectionin the arterial system;

[0197] a vascular compliance; and

[0198] a blood flow resistance at the distal section in the arterialsystem; which are based on the condition of the circulatory system,

[0199] In the following, the relation between the four elements of theelectrical model and the four parameters will be explained.

[0200] Inductance L:

[0201] the blood flow momentum at the proximal section in the arterialsystem

[0202] (dyn·s² /cm⁵)

[0203] static electrical capacity C:

[0204] the compliance at the proximal section in the arterial system(elasticity)

[0205] (cm⁵/dyn)

[0206] The compliance refers to the elasticity of the blood vessels tosignify their softness.

[0207] electrical resistance Rc:

[0208] the vascular resistance due to blood flow at the proximal sectionin the arterial system

[0209] (dyn·s/cm⁵)

[0210] electrical resistance Rp:

[0211] the vascular resistance due to blood flow at the distal sectionin the arterial system

[0212] (dyn·s/cm⁵)

[0213] The electrical currents i, ip, ic, flowing in the varioussections of the electrical model correspond to the blood flow rate(cm³/s) in the corresponding sections. The general voltages e(t),applied to the various sections of the model correspond to the pressure(dyn/cm²) at the aorta ascendens. The terminal voltage VP of the staticelectrical capacity C corresponds to the blood pressure at the radialartery.

[0214] (2) Approximate Formulas of Response in the Model

[0215] Next, the response of the electrical model will be theoreticallyexplained with reference to FIG. 12. Firstly, the following differentialequation will be formed using the four parameters in the Model shown inFIG. 12, $\begin{matrix}{{e(t)} = {{R_{c}i} + {L\quad \frac{i}{t}} + {v_{p}.}}} & (1)\end{matrix}$

[0216] Here, the current i is: $\begin{matrix}{\begin{matrix}{i = {i_{c} + i_{p}}} \\{= {{C\frac{v_{p}}{t}} + \frac{v_{p}}{R_{p}}}}\end{matrix}.} & (2)\end{matrix}$

[0217] Therefore, the above equation (1) can be expressed as:$\begin{matrix}{{e(t)} = {{{LC}\quad \frac{d^{2}v_{p}}{{dt}^{2}}} + {R_{c}C} + {\frac{L}{R_{p}}\quad \frac{v_{p}}{t}} + 1 + {\frac{R_{c}}{R_{p}}{v_{p}.}}}} & (3)\end{matrix}$

[0218] t is known that the general solution to a differential equationsuch as the above equation (3) is obtained from the sum of a particularsolution satisfying equation (3) and a transient solution satisfying thefollowing equation: $\begin{matrix}{0 = {{{LC}\quad \frac{d^{2}v_{p}}{{dt}^{2}}} + {R_{c}C} + {\frac{L}{R_{p}}\frac{v_{p}}{t}} + 1 + {\frac{R_{c}}{R_{p}}{v_{p}.}}}} & {(4).}\end{matrix}$

[0219] Next, a method of solving the above equation (4) will beexplained. Firstly, suppose that an attenuating wave vp is expressed asfollows:

v_(p)=Ae^(st)  (5).

[0220] Substituting the above equation (5) in the equation (4),$\begin{matrix}{{{LCs}^{2} + R_{c} + {\frac{L}{R_{p}}s} + 1 + {\frac{R_{c}}{R_{p}}v_{p}}} = 0.} & (6)\end{matrix}$

[0221] Here, we solve the above equation (6) for s as follows:$\begin{matrix}{s = {\frac{{{- R_{c}}C} + {\frac{L}{R_{p}} \pm \sqrt{{R_{c}C} + \frac{L^{2}}{R_{p}} - {4{LC}\quad 1} + \frac{R_{c}}{R_{p}}}}}{2{LC}}.{If}}} & (7) \\{{{{R_{c}C} + \frac{L^{2}}{R_{p}}} < {{4{LC}\quad 1} + \frac{R_{c}}{R_{p}}}},} & (8)\end{matrix}$

[0222] then the value of the root in the equation (7) is negative, andthe equation (7) will be expressed as follows: $\begin{matrix}{\begin{matrix}{s = \frac{{{- R_{c}}C} + {\frac{L}{R_{p}} \pm {j\sqrt{{{- R_{c}}C} + \frac{L^{2}}{R_{p}} + {4{LC}\quad 1} + \frac{R_{c}}{R_{p}}}}}}{2{LC}}} \\{= {{- \alpha} \pm {j\quad \omega}}}\end{matrix},\text{here,}} & (9) \\{\begin{matrix}{\alpha = \frac{R_{c} + \frac{L}{R_{p}}}{2{LC}}} \\{= \frac{L + {R_{p}R_{c}C}}{2{LCR}_{p}}}\end{matrix}\text{and}} & (10) \\{{\omega = \frac{{{- R_{c}}C} + \frac{L^{2}}{R_{p}} + {4{LC}\quad 1} + \frac{R_{c}}{R_{p}}}{2{LC}}}\text{Next, letting:}} & (11) \\{{A_{1} = {LC}},} & (12) \\{{A_{2} = \frac{L + {R_{c}R_{p}C}}{R_{p}}},\quad {and}} & (13) \\{{A_{3} = \frac{R_{c\quad} + R_{p}}{R_{P}}},} & (14)\end{matrix}$

[0223] each of the above equations (10) and (11) will be expressed asfollows: $\begin{matrix}{\alpha = {\frac{A_{2}}{2A_{1}}\quad {and}}} & (15) \\{\omega = {\sqrt{\frac{A_{3}}{A_{1}} - \alpha^{2}}.}} & (16)\end{matrix}$

[0224] Thus, the value s is finally decided, and the solution satisfyingthe equation (4) can be obtained. In accordance with the above analysis,the equation (5) is utilized as an approximate equation expressing theattenuating and vibrating components, included in the response wave ofthe electrical model.

[0225] Next, the blood pressure waves at the aorta ascendens aremodeled. FIG. 13 shows general pressure waves at the aorta ascendens.Therefore, we approximate the pressure waves with triangular pulse wavesshown in FIG. 14. Letting the amplitude and the time be the voltages E 0and Em and be the time t_(p) and tp1 , the pressure waveform e(t) at atime t can be expressed as follows: $\begin{matrix}{{{et} = {E_{0} + {E_{m}1} - \frac{t}{t_{p1}}}},{{{\text{when}\quad 0} \leq t < t_{p1}};{and}}} & (17) \\{{e(t)} = E_{0}} & (18)\end{matrix}$

[0226] when t_(p1)≦t<t_(p):

[0227] where E 0 is the voltage to give minimum blood pressure;

[0228] (E 0 +Em) is the voltage to give a maximum blood pressure;

[0229] t_(p) is the period for one pulsation; and

[0230] tp1 is the period from the point of rise to the minimum point ofthe blood pressure at the aorta ascendens.

[0231] When the waveform e(t), expressed as the above equation (17) and(18), is inputted to the electrical model shown in FIG. 12, the responsewaveform v_(p)(t) is: $\begin{matrix}{{{v_{p}(t)} = {E_{\min} + {B\quad 1} - \frac{t}{t_{b}} + {D_{m1}^{{- \alpha}\quad t}\sin \quad \omega \quad t} + \theta_{1}}}{{{\text{when}\quad 0} \leq t < t_{p1}},}} & (19) \\{{{v_{p}(t)} = {E_{\min} + {D_{m2}^{{{- \alpha}\quad t} - t_{p1}}\sin \quad \omega \quad t} - t_{p1} + \theta_{2}}}{{{and}\quad {when}\quad t_{p1}} \leq t < {t_{p}.}}} & (20)\end{matrix}$

[0232] The third term on the right in the equation (19) and the secondterm on the right in the equation (20) designate the attenuatingcomponents (corresponding to the equation (5)), and α and ω are given bythe above equations (15) and (16).

[0233] (3) The Relation between Each Element of the Model and RadialArterial Waveform

[0234] Next, other constants in the equations (19) and (20) except α andω will be discussed. Firstly, substituting equations (17) and (19) inthe above differential equation (3), the following equation (21) can beobtained. $\begin{matrix}\begin{matrix}{{E_{0} + {E_{m}1} - \frac{t}{t_{p1}}} = \quad {1 + {\frac{R_{c}}{R_{p}}E_{\min}} + B - {\frac{B}{t_{b}}R_{c}C} + {\frac{L}{R_{p}}t} +}} \\{\quad {{{LC}\quad \alpha^{2}} - {\omega^{2}D_{m1}} - {\alpha \quad D_{m1}R_{c}C} + \frac{L}{R_{p}} +}} \\{\quad {{D_{m1}1} + {\frac{R_{c}}{R_{p}}^{{- \alpha}\quad t}\sin \quad \omega \quad t} + \theta_{1} +}} \\{\quad {{\omega \quad D_{m1}R_{c}C} + \frac{L}{R_{p}} -}} \\{\quad {{2{LC}\quad \alpha \quad \omega \quad D_{m1}^{{- \alpha}\quad t}\cos \quad \omega \quad t} + \theta_{1}}}\end{matrix} & (21)\end{matrix}$

[0235] For the equation (21) to be valid, the following conditions arenecessary, $\begin{matrix}{\begin{matrix}{{E_{0} + E_{m}} = {1 + {\frac{R_{c}}{R_{p}}E_{\min}} + B}} \\{= {E_{0} + {A_{3}B} - {\frac{B}{t_{b}}A_{2}}}}\end{matrix},} & (22) \\{\begin{matrix}{\frac{E_{m}}{t_{p1}} = {{\frac{B}{t_{b}}1} + \frac{R_{c}}{R_{p}}}} \\{= \frac{B}{A_{3}t_{b}}}\end{matrix},} & (23) \\{{{{{LC}\quad \alpha^{2}} - \omega^{2} - {\alpha \quad R_{c}C} + \frac{L}{R_{p}} + 1 + \frac{R_{c}}{R_{p}}} = 0}{and}} & (24) \\{{{R_{c\quad}C} + \frac{L}{R_{p}}} = {2{LC}\quad \alpha}} & (25)\end{matrix}$

[0236] Because α and ω are given by the above equations (15) and (16),it is natural that α and ω satisfy equations (24) and (25).

[0237] Secondly, substituting equations (18) and (20) in the abovedifferential equation (3), the following equation (26) can be obtained:$\begin{matrix}\begin{matrix}{E_{0} = \quad {1 + {\frac{R_{c}}{R_{p}}E_{\min}} + {{LC}\quad \alpha^{2}} - {\omega^{2}D_{m2}} - {\alpha \quad D_{m2}R_{c}C} + \frac{L}{R_{p}} +}} \\{\quad {{\frac{R_{c}}{R_{p}}^{{{- \alpha}\quad t} - t_{p1}}\sin \quad \omega \quad t} - t_{p1} + \theta_{2} + {\omega \quad D_{m2}R_{c}C} +}} \\{\quad {\frac{L}{R_{p}} - {2{LC}\quad {\alpha\omega}\quad D_{m2}^{{{- \alpha}\quad t} - t_{p1}}\cos \quad \omega \quad t} - t_{p1} + \theta_{2}}}\end{matrix} & (26)\end{matrix}$

[0238] For the equation (26) to be valid, in addition to the equations(23) and (24), the following equation (27) must be satisfied that:$\begin{matrix}{\begin{matrix}{E_{0} = {1 + {\frac{R_{c}}{R_{p}}E_{\min}}}} \\{= {A_{3}E_{\min}}}\end{matrix}.} & (27)\end{matrix}$

[0239] The constants in the equations (19) and (20) will be computed inaccordance with the above equations (22)˜(25) and (27) which define thedifferential equation (3). From equation (27), $\begin{matrix}{E_{\min} = {\frac{E_{0}}{A_{3}}.}} & (28)\end{matrix}$

[0240] While, from equation (23), B is expressed as follows:$\begin{matrix}{B = {\frac{E_{m}t_{b}}{A_{3}t_{p1}}.}} & (29)\end{matrix}$

[0241] Here, substituting the equation (29) in the equation (22), tb isexpressed as follows: $\begin{matrix}{t_{b} = {\frac{{A_{3}t_{p1}} + A_{2}}{A_{3}}.}} & (30)\end{matrix}$

[0242] Next, the remaining constants D 1m, D 2m, θ 1 and θ 2 areselected so that the radial arterial waveform v_(p) can be contiguous att=0, tp1 , and t_(p). In other words, the values are selected so as tosatisfy the following conditions (a)˜(d).

[0243] (a) the coincidence of v_(p)(tp1 ) in the equation (19) withv_(p)(tp1 ) in the equation (20)

[0244] (b) the coincidence of v_(p)(t_(p)) in the equation (20) withv_(p)(0) in the equation (19)

[0245] (c) the coincidence of the differential coefficient in theequation (19) with one in the equation(20) when t=tP

[0246] (d) the coincidence of the differential coefficient it in theequation (19) at t=0 with the differential coefficient in the equation(20) at the time t=tP

[0247] That is, the values of D 1m and θ 1 are as follows:$\begin{matrix}{{D_{1m} = \frac{\sqrt{D_{11}^{2} + D_{12}^{2}}}{\omega}},} & (31) \\{{\theta_{1} = {\tan^{- 1}\frac{D_{11}}{D_{12}}}},} & (32)\end{matrix}$

[0248] where

D ₁₁ =v ₀₁ −B−E _(min)ω  (33) $\begin{matrix}{D_{12} = {v_{01} - B - {E_{\min \quad}\alpha} + \frac{B}{t_{b}} + {\frac{i_{01}}{C}.}}} & (34)\end{matrix}$

[0249] Here, v 01 is the initial value of v_(p) and i 01 is the initialvalue of i_(p) when t=0.

[0250] Also, the values of D 2m and θ 2 are as follows: $\begin{matrix}{D_{2m} = \frac{\sqrt{D_{21}^{2} + D_{22}^{2}}}{\omega}} & (35) \\{{\theta_{2} = {\tan^{- 1}\frac{D_{21}}{D_{22}\quad}}},} & (35)\end{matrix}$

[0251] where

D ₂₁ =v ₀₂ −E _(min)ω  (36) $\begin{matrix}{D_{22} = {v_{02} - {E_{\min}\alpha} + {\frac{i_{02}}{C}.}}} & (37)\end{matrix}$

[0252] Here, v 02 is the initial value of v_(p) and i 02 is the initialvalue of ic when t=tp1 . The constants in the equation (19) and (20) arethus obtained.

[0253] Thirdly, by back-computing the angular frequency ω in theequation (16), the blood resistance RC at the artery center can beexpressed as follows: $\begin{matrix}{R_{c} = {\frac{L - {2R_{p}\sqrt{{LC1} - {\omega^{2}{LC}}}}}{{CR}_{p}}.}} & (39)\end{matrix}$

[0254] The condition necessary to make the resistance Rreal and positivethat: $\begin{matrix}{\frac{4R_{p}^{2}C}{1 + {2\omega \quad R_{p}C^{2}}} \leq L \leq {\frac{1}{\omega^{2}C}.}} & (40)\end{matrix}$

[0255] Generally, the R_(p) is at a level of about 10³ (dyn·s/cm⁵) andthe C is about 10⁻⁴ (cm⁵ /dyn), and because the ω is the angularfrequency of the vibration component superimposed on the arterial pulsewaves, the angular frequency o) can be considered to be over 10 (rad/s),and therefore the lower limit value of the equation (40) can be regardedas 1/ω²C. For simplification, L can be approximated by: $\begin{matrix}{{L = \frac{1}{\omega^{2}C}},} & (41)\end{matrix}$

[0256] then the resistance R_(c) becomes: $\begin{matrix}{R_{c} = {\frac{L}{{CR}_{p}}.}} & (42)\end{matrix}$

[0257] Using equations (41) and (42), the attenuation constant α in theequation (15) is expressed as follows: $\begin{matrix}{\alpha = {\frac{1}{{CR}_{p}}.}} & (43)\end{matrix}$

[0258] Using the equations (41)˜(43) and either α, ω or one of the fourparameters, for example L, the other parameters Rc, Rp and C areexpressed as follows:

R _(c)=αL  (44), $\begin{matrix}{{R_{p} = \frac{\omega^{2}L}{\alpha}},} & (45) \\{C = {\frac{1}{\omega^{2}L}.}} & (46)\end{matrix}$

[0259] It is clear that the parameters of the model are finally decidedby α, ω and L based on the equations (44)˜(46).

[0260] Here, α and ω can be obtained by the actual measured waveforms ofthe radial arterial pulse waves. On the hand, L can be computed from thestroke volume SV per one pulsation (beat).

[0261] Next, the process of computing L based on the stroke volume SVwill be explained. Firstly, the average E 01 of the pressure wave at theaorta ascendens is given by $\begin{matrix}{E_{01} = {\frac{{E_{0}t_{p}} + \frac{E_{m}t_{pl}}{2}}{t_{p}}.}} & (47)\end{matrix}$

[0262] On the hand, the Rc, Rp, α, ω and L are related by the followingequation: $\begin{matrix}{{R_{c} + R_{p}} = {{{\alpha \quad L} + \frac{\omega^{2}L}{\alpha}} = {\frac{\alpha^{2} + {\omega^{2}L}}{\alpha}.}}} & (48)\end{matrix}$

[0263] Next, the average current through the four parameters model, thatis the value of the average E 01 divided by (Rc+Rp), corresponds to anaverage value of a blood flow (SV/t_(p)) in the artery caused by theheart pulsing motion. Therefore, $\begin{matrix}{\frac{SV}{t_{p}} = {1333.22 \cdot \frac{{\alpha \quad E_{0}t_{p}} + \frac{E_{m}t_{pl}}{2}}{\alpha^{2} + {\omega^{2}{Lt}_{p}}}}} & (49)\end{matrix}$

[0264] where the (1333.22) is the coefficient for conversion in thepressure unit from (mmHg) to (dyn/cm²).

[0265] The given equation (49) is solved for L, then the following canbe obtained to compute L from the stroke volume SV. $\begin{matrix}{L = {1333.22 \cdot {\frac{{\alpha \quad E_{0}t_{p}} + \frac{E_{m}t_{pl}}{2}}{\alpha^{2} + {\omega^{2}{SV}}}.}}} & (50)\end{matrix}$

[0266] It is possible to obtain the inductance L by measuring the bloodflow rate to determine the value to correspond to the average current:$\frac{1}{t_{p}} = {{E_{0}t_{p}} + \frac{E_{m}t_{pl}}{2}}$

[0267] in the above equation (49). The known methods of measuring theblood flow rate are impedance method and Doppler method. The Dopplermethod can be performed by either ultrasound or laser.

[0268] (4) Expansion of the Electrical Model

[0269] Next, the Model shown in FIG. 12 can be expanded to consider thepressure variations at the locations of Chun, Guan and Chi, then acircuit shown in FIG. 26 is obtained.

[0270] In this figure, the pressures at the aorta ascendens, Chi, Guanand Chun are expressed by the general voltages eo(t), e 1 (t), e 2 (t)and e 3 (t), respectively, and the inductance L 1 ˜L 3 , representingthe inertia of the blood, the static electrical capacity C 1 ˜C 3 ,representing the vascular compliance and the resistances Rc1 ˜R 3 ,representing the resistance of the blood vessels are connected betweenthe voltage measuring terminals.

[0271] Also, the electrical resistance R_(p) in FIG. 12 represents thevascular resistance in further distal blood vessels than the arterialdistal blood vessel which are to be measured. Therefore, in the Modelpresented in FIG. 26, the electrical resistance shown R_(p) in FIG. 12corresponds to the combined impedance in the later stages of thecircuit. For example, in FIG. 26, if the combined impedance to the rightside of the single dot line A-A′ is equated to the electrical resistanceR_(p), the model in FIG. 26 becomes the same as the Model in FIG. 12.

[0272] Therefore, in the Expansion Model shown in FIG. 26, it ispossible to obtain the values of the elements of the Expansion Model bythe same technique employed in the Model in FIG. 12. That is, if thecombined impedance to the right side of the single dot line A-A′ isequated to the electrical resistance R_(p), according to the methodpresented above, the parameters Rc1 , L 1 and C 1 are obtained on thebasis of the waveforms of the general voltages eo(t) and e 1 (t),similarly the parameters Rc2 , L 2 and C 2 are obtained on the basis ofthe waveforms of the general voltages e 1 (t) and e 2 (t), and similarlythe parameters RC3 , L 3 , C 1 and Rp3 are obtained on the basis of thewaveforms of the general voltages e 2 (t) and e 3 (t).

[0273] In the above explanation, the waveforms corresponding to thegeneral voltages e 1 (t)˜e 3 (t) are assumed to represent the at-sourceblood pressure directly. However, in practice, the waveforms, generatedin the blood vessels of the examinee, are changed while being propagatedthrough the muscles, fat tissues and skin of the examinee before beingdetect by the strain gages 252˜254.

[0274] Therefore, in order to carry out more detailed analysis, it isnecessary to consider the pressure waveforms. It is suggested that, insuch a case, it would be suitable to provide a pressure waveformtransformation circuits 270˜272 as shown in FIG. 26. In the circuit 270,the numeral 273 represents a voltage follower circuit; 274, 275 areelectrical resistances, 276 is a condenser. The electrical resistances274, 275 simulate the blood pressure drop between the strain gage 254and the location to correspond to the Chi of the artery of the examinee.The electrical resistance 275 and the condenser 276 simulate thefrequency response, i.e. the decay in the high frequency waveforms. Thevoltage follower circuit 273 is provided before the electricalresistance 274 because it is considered that the effects of the muscle,fat tissues and skin on the artery itself is slight.

[0275] In this model, the voltage e 1 (t) is transformed by the pressurewaveform transformation circuit 270 and is detected as e 1 ′(t).Therefore, to obtain the correct waveform of the voltage el, it isnecessary to obtain the constants for each element in the pressurewaveform transformation circuit 270. This is possible by applying soundsignals of various frequencies and waveforms to the examenee's arm, andanalyzing the attenuation and changes in such sound signals. That is,because the configuration of the circuit of the pressure waveformtransformation circuit 270 is the same as the Model shown in FIG. 12,the same method can be used. Here, it should be noted that the values inthe circuit 270 are not fixed, and change in accordance with the fingerpressures of the examiner; therefore, it is preferable to record theresults of applying various sound signals under various finger pressureon the examinee's arm, so as to relate the constants to the variouspressing pressures.

[0276] The above descriptions provided an explanation of therelationship among the radial arterial waveforms, stroke volume and eachof the elements in the electrical Model. The microcomputer 204 (See FIG.10) in this embodiment computes the values of the parameters in themodel in accordance with the relationship presented in the foregoing.

[0277] Chapter 2-2: Operation of the Apparatus

[0278] FIGS. 15 to 19 show flowcharts for the operation of the waveformanalysis apparatus. FIG. 20 shows the waveforms of the radial arteryobtained by the averaging process, FIG. 21 shows the comparison betweenthe radial artery waveforms W1 obtained by the averaging process and theradial artery waveforms W2 obtained by the parameter computation. Thefollowing explanations are provided with reference to these figures.

[0279] Chapter 2-2-1: Ordinary Computation Procedure

[0280] (1) Reading of Pulse Wave Data The computation of the circulatorydynamic parameters is performed by: attaching the cuff belt S2 to theexaminee as shown in FIG. 11; attaching the pulse wave sensor S1 to thehand of the examiner; pressing down the switch 266 a (see FIG. 25); andinputting various commands through the keyboard 205. In response tothese commands, the microcomputer 204 sends a command to beginmeasurements of the pulse waves to the pulse wave detection apparatus201. The pulse wave detection apparatus 201 receives the radial arterypulse wave signals through the strain gages 252˜254, and the sequentialdigital signals expressing the radial pulse waves are outputted from theA/D converter 203, and the microcomputer 204 takes in the readings for aset period of time (about one minute). Thus the microcomputer 204accumulates sequential digital signals of the plurality of waveforms ofthe pulsation's.

[0281] (2) Averaging Process

[0282] Next, the microcomputer 204 computes an average waveform duringthe one-minute-period based on the plurality of waveforms of the radialartery, and stores this waveform as the representative waveform of theradial artery in the internal memory (step S1). At the same time,averaging is performed on the finger pressures detected via thedecrementor 267 (see FIG. 25). A representative waveform W1 of theradial artery stored in the memory is shown in FIG. 20.

[0283] (3) Stroke Volume Computation

[0284] When the above averaging process is completed, the microcomputer204 sends out a command to activate the stroke pulsing volumedetermination device 202. The results of the measurement data perpulsation is forwarded to the microcomputer 204 (step S2).

[0285] (4) Parameter Computation Process

[0286] Next, the processing by the microcomputer 204 proceeds to stepS3, and performs the parameter computation routine whose flowcharts areshown in FIGS. 16 and 17. With the execution of this routine, theroutine of computing α and ω (steps S109 and S117) shown in FIG. 18, isexecuted for each of the Chun, Guan and Chi locations. With theexecution of these α and ω computing routines, the ω computing routineis performed (step S203). To simplify the explanation, it is assumedthat the pressure waveforms corresponding to the electrical voltages e 1(t)˜e 3 (t) in FIG. 26 are obtained directly from the strain gages252˜254.

[0287] The following is an explanation of the routines described above.

[0288] First, the microcomputer 204 examines the radial artery waveformsper pulse in the memory, and determines the first point P 1 in terms ofthe time t 1 and blood pressure level y 1 corresponding to the maximumblood pressure; the second point P 2 in terms of the time t 2 and bloodpressure level y 2 corresponding to the temporary drop in the bloodpressure; and the third point P 3 in terms of the time t 3 and bloodpressure y 3 corresponding to the next rise in the blood pressure. Also,the microcomputer 204 determines the time duration t_(p), the minimumblood pressure value E_(min) (which corresponds to the 1st term of eachof the equations (3) and (4) ) with respect to one pulsation of theradial arterial waveforms in the memory (step S101). The aboveprocessing produces the following data, for example, necessary for theparameters computation. First Point: t₁ = 0.104 s, y₁ = 123.4 mmHgSecond Point: t₂ = 0.264 s, y₂ = 93.8 mmHg Third Point: t₃ = 0.380 s, y₃= 103.1 mmHg Pulse duration: t_(p) = 0.784 s Min. Press: E_(min) = 87.7mmHg Stroke vol.: SV = 103.19 cc/beat

[0289] In this case, when the pulse waveform is such that it isdifficult to distinguish the second point P 2 from the third point P 3 ,then the times for the point P 2 and P 3 are chosen as t₂ = 2t₁, t₃ =3t₁,

[0290] and the blood pressure value is determined at these points.

[0291] To simplify the calculations, using the value of the bloodpressure yo at the point A shown in FIG. 22, y 1 to y 3 are normalizedin steps S102, 103, and the initial value of B is determined as:$\frac{y_{0}}{2} - 0.1$

[0292] in step S104.

[0293] Next, the optimum values of the B, tb, α and ω are obtained bythe following steps.

[0294] (a) First, B is varied between y 0 /2 to y 0 , and simultaneouslyis varied between t_(p)/2 to t_(p) at an interval of +0.1, and thevalues of B, t_(b), α and ω are determined so as to minimize V_(p)(t 1)−y 1 , v_(p)(t 2 )−y 2 and v_(p)(t 3 )−y 3 .

[0295] (b) For the values of B, tb, α and ω the values of B, t_(b), αand ω are determined so as to minimize the values of V_(p)(t 1 )−y 1 ,v_(p)(t 2)−y 2 and v_(p)(t 3 )−y 3.

[0296] (c) Based on the values of the B and tb, repeat the steps (a) and(b) within the range of B

B±0.05, t_(b)±0.05

[0297] (d) In the above process (a), (b) and (c), the value of α isvaried in increments of 0.1 between 3 to 10 to calculate the optimumvalues of ω for each α. The values of ω and α are determined so as tomake $\frac{{v_{p}}t_{2}}{t} = 0$

[0298] by the binary method (refer to FIG. 10). Furthermore, the valuesof v_(p) are calculated with the initial value of v 01 =0.

[0299] According to the above procedure, the following example valuesare determined. α = 4.2 (s⁻¹); ω = 24.325 (rad/s); B = 27.2 (mmHg);t_(b) = 0.602 (s)

[0300] (e) Next, the values of tp1 , Em and E 0 are calculated from theequations (28)˜(30), and (44)˜(46) in steps S123, S124. The results ofthis example is shown below.

[0301] tp1 =0.588(s)

[0302] Em=46.5 mmHg

[0303] E 0 =90.3 mmHg

[0304] (f) Next, using the equation (50), the value of L from thepulsing volume rate in step S125, and the remaining parameters areobtained from the equations (44)˜(46) in step S126. The followingexamples values are obtained. L = 7.021 (dyn · s²/cm⁵) C = 2.407 × 10⁻⁴(cm⁵/dyn) R_(c) = 29.5 (dyn · s/cm⁵) R_(p) = 989.2 (dyn · s/cm⁵)

[0305] Also, total direct current resistance (averaging) value TPR(Total Peripheral Resistance) is obtained by the following equation.

TPR=R c +R p=1018.7(dyn·s/cm⁵)

[0306] (5) Output Processing

[0307] When the above discussed parameter processing is completed, themicrocomputer 204 outputs the values of L, C, Rc and R_(p) from theoutput device in step S4. That is, for each waveform from the Chun,Guan, Chi sections, the above computation processes are performed, andthe values of the parameters L 1 to L 3 , C 1 to C 3 , Rc1 to Rc3 shownin FIG. 26 are obtained.

[0308] For confirmation, the parameter values computed are put inequation (40), then

6.696≦L≦7.021

[0309] is obtained, and the approximation by equation (41) appears to beproper. Also, as shown in FIG. 21, the radial arterial waveformscalculated from the parameter values are quite similar to those actuallyobserved by averaging over one minute period.

[0310] Chapter 2-2-2: Continuous Computation

[0311] The embodiment according to this invention is provided with atimer, and it is possible to measure the circulatory dynamic parameterscontinuously over a prolonged period of time. To perform continuousmeasurements, the examiner inputs a command for continuous measurementthrough the keyboard 205. When the resulting step S4 (output process)shown in FIG. 15 is completed, the timer is set, and after a set timehas elapsed, the steps from S1 are re-executed, the parameters arecomputed in step S3, and the results are recorded in a recording mediumin step S4. By repeating this process, the continuous computations ofthe parameters are performed.

[0312] The examiner may alter the finger pressure suitably after eachelapsing of a set time period. That is, in a general pulse examination,the examiner alters his finger pressure suitably to obtain informationon various items, therefore the present embodiment may also be used inconjunction with such an examination procedure. By so doing, it becomespossible to obtain various data in accordance with the varying fingerpressures.

[0313] Chapter 2-3: Variations of the Second Embodiment

[0314] In addition to the second embodiment presented above, thefollowing variations may be practiced.

[0315] Variation (i)

[0316] The circulatory dynamic parameters for the radial artery may beobtained without measuring the stroke volume, and assuming the value ofL. To supplement lowering of the computational accuracy, the embodimentmay be configured so as to have an overlap display of the computed andmeasured radial artery waveforms as shown in FIG. 21, and to have theexaminer enter various values of L. In such an embodiment, the examinerperforms trial and error process of optimizing the value of L to obtainmatching of the two waveforms.

[0317] Variation (ii)

[0318] As a model of the radial artery waveform, a waveform shown inFIG. 23, a step-and-ramp waveform may be chosen instead of a triangularwaveform. This form is closer to the true waveform than the triangularwaveform, and more accurate representation for the circulatory dynamicparameters is obtainable.

[0319] Variation (iii)

[0320] In the above embodiment, the dynamic parameters were obtained bymeans of equations and computations, the waveforms may be simulated byvarying the parameters within ranges by a simulation circuitry, and theparameters which represent the measured waveforms most accurately may beoutputted. In this case, more complex electrical models for the arterialsystem and for the pressure waveforms for the aorta ascendens may bechosen to obtain more accurate representation of the actual performance,and the measurement accuracy can be improved.

[0321] Variation (iv)

[0322] The measurement locations for the radial artery and the strokevolume are not limited to those shown in FIG. 11. For example, byproviding blood pressure sensor on the rubber glove 251, both the radialarterial waveforms and the stroke volume may be determinedsimultaneously. In this case, the examinee does not need to roll up thesleeves, and it is more convenient, in some cases.

[0323] Similarly, the stroke volume determination device may be made onarm, hand or finger on the arm opposite to the pulse taking arm.

[0324] Variation (v)

[0325] In the above embodiment, to simplify the explanation, thewaveforms corresponding to the voltages e 1 ˜e 3 were assumed to beobtained directly from the strain gages 252˜254, but it is permissibleto examine using a model that incorporates the model for the pressurewaveform transformation circuits 270˜272.

[0326] Chapter 3: A Diagnostic Apparatus Based on Distortions in thePulse Waveforms

[0327] Next, a diagnostic apparatus according to a third embodiment ofthe present invention will be explained. This apparatus first determinesthe distortions of the detected pulse waveforms obtained from anexaminee.

[0328] The distortion in the waveforms refers to deviations from the“normal” pulse waveform shape of a living body, and the waveform shapeis obviously closely related to the conditions of the living body, andtherefore, computations of distortions in the waveforms serve as anexcellent guide to diagnostics.

[0329] As will be described later in this Chapter, the waveformdistortions are also related to the circulatory dynamic parametersdescribed in Chapter 2, and therefore, computations of the waveformdistortions will also serve as indicators for circulatory dynamicparameters, and will enable diagnosis to be performed based on computeddistortions.

[0330] In this Chapter, the relationship between waveform distortionsand waveform types/circulatory dynamic properties will be explainedfirst, followed by the presentation of a diagnostic apparatus of a thirdembodiment which utilizes this relationship, and a variation of thethird embodiment.

[0331] Chapter 3-0: Relationship between Distortion, Pulse WaveformShape and Dynamic Parameters

[0332] Before explaining the operations of the pulse wave diagnosticapparatus of this invention, the relationship between the waveformdistortion, the pulse waveform shape and circulatory dynamic parameterswill be explained with reference to the drawings provided on the basisof the inventors experience. In the following embodiment, the distortionfactor d is defined as follows:$d = \frac{\sqrt{Q_{2}^{2} + Q_{3}^{2} + \ldots \quad + Q_{n}^{2}}}{Q_{1}}$

[0333] where Q 1 is the amplitude of the fundamental wave;

[0334] Q 2 is the amplitude of the 2nd harmonics; and

[0335] Qn is the amplitude of the nth harmonics in the Fourier analysisof the pulse waves.

[0336] Chapter 3-0-1: Relationship between Waveform Distortion andWaveform Shape

[0337] First, the relationship between the waveform distortion andwaveform shapes of the pulse waves will be explained.

[0338] From a variety of shapes of pulse waveforms, those defined asPing mai type, Hua mai type and Xuan mai type waveforms are typicallyillustrated in FIGS. 31A, 31B and 31C, respectively. The graphs showblood pressure BP in mmHg plotted on the vertical axis and the time inseconds plotted on the horizontal axis.

[0339] The Ping mai is typical shape of a healthy adult, and thewaveform shown in FIG. 31A is from a 34-year-old male. The Ping mai typewaveform is characterized by a gentle double peak waveform having aregular rhythm, and is free of irregularities.

[0340] The Hua mai is caused by hemodynamic irregularities, and issymptomatic of an illness causing rapid pulsations of the heart. Atypical example shown in FIG. 31B is from a 28-year-old male patient.The Hua mai type waveform is characterized by a rapid rise and fall inthe blood pressure, and by the steeply rising and falling second peak.

[0341] The Xuan mai is caused by vascular hardening and is symptomaticof an illness including liver and kidney ailments. This waveform isassociated with tensions in the autonomic nerve system to cause thewalls of the blood vessels to stiffen, and the blood pulsations cannotbe properly reflected in the pulse waveform. A typical example is shownin FIG. 31C which is taken from a 34-year-old male patient. The Xuan maitype waveform is characterized by a rapid rise followed by a gradualdrop in the blood pressure over a period of time.

[0342]FIG. 32 is a bar graph showing the variations of the distortionfactor d in Hua mai, Ping mai and Xuan mai waveform shapes, and showsthe analytic results of many examinations (21 cases of Hua mai, 35 casesof Ping mai, 22 cases of Xuan mai).

[0343] It is shown that in the Ping mai type the pulsing pressure iscentered around a distortion factor d at 0.907 with a deviation of±0.05; in the Hua mai type, the distortion factor d is larger than theone of the Ping mai type at 1.013 with a deviation of ±0.148; in theXuan mai type, the distortion factor d is the smallest of the threetypes, and is centered around 0.734 with a deviation of ±0.064.

[0344] The statistical significance of the distortion factors of thewaveform types was analyzed by t-test, and it was found that thedifferences in the waveform shapes were statistically significant withuncertainty of less than 0.05.

[0345] Chapter 3-0-2: Relationship between Waveform Distortion andCirculatory Parameters

[0346] Second, the relationship between the waveform distortion and thecirculatory dynamic parameters described in Chapter 2-1-1 will beexplained.

[0347] The relationships of the distortion factor d to the circulatorydynamic parameters are shown in FIG. 33 to 36. These data were takenfrom a experiment of 120 cases. FIG. 33 shows the relationship of thedistortion factor d to the proximal vascular resistance Rc, which isexpressed mathematically as:

R_(C)=58.68·d^(0.394)

[0348] where the correlation coefficient r=−0.807

[0349]FIG. 34 shows the relationship between the distortion factor d andthe distal vascular resistance Rp which is expressed as:

R_(p)=2321·e^(−0.615) d

[0350] where the correlation coefficient r=−0.418

[0351]FIG. 35 shows the relationship between the distortion factor d andthe momentum L, which is expressed as:

L=162.8·e⁻²⁵⁸⁵ d

[0352] where the correlation coefficient r=−0.774

[0353]FIG. 36 shows the relationship of the distortion factor d to thecompliance C, which is expressed as:

C=10⁻⁴ −1.607+3.342·d

[0354] where the correlation coefficient r=0.764.

[0355] Chapter 3-0-3: Relationship between Circulatory Parameters andWaveform Shape

[0356] Just for, the relationship between the circulatory parameters andwaveform shape will be explained.

[0357] FIGS. 37 to 40 are bar graphs showing the four circulatorydynamic parameters for the three waveform types: Hua mai, Ping mai andXuan mai. FIG. 37 shows the proximal resistance Rc for the threewaveform types. The resistance is the smallest in the Hua mai type at47.048±18.170 (dyn·s/cm⁵) The next smallest is the resistance in thePing Mai type at 92.037±36.494 (dyn·s/cm⁵). The largest resistance isexhibited in the Xuan mai type at 226.093±61.135 (dyn·s/cm⁵).

[0358]FIG. 38 shows the distal section resistance R_(p) for the threewaveform types. In this case, the Hua mai type exhibits the smallestresistance at 1182.1±176.7 (dyn·s/cm⁵); followed by the Ping mai type at1386.5±228.3 (dyn·s cm⁵); and the Xuan type mai type exhibits thelargest resistance at 1583.0±251.0 (dyn·s/cm⁵)

[0359]FIG. 39 shows the momentum L of the blood flow for the threewaveform types. The momentum is the smallest in the Hua mai type at10.337±2.609 (dyn·s²/cm⁵); followed by that in the Ping may type at16.414±4.604 (dyn·s²/cm⁵); and the largest L is in the Xuan mai type at27.550±5.393 (dyn·s²/cm⁵)

[0360]FIG. 40 shows the compliance C for the three waveform types. Thelargest compliance is exhibited by the Ping mai type at(2.030±0.554)·10⁻⁴ (cm⁵/dyn); followed by the Ping mai type at(1.387±0.311) 10⁻⁴ (cm/dyn); and the Xuan mai type has the smallestcompliance at (0.894±0.207)10⁻⁴ (cm⁵/dyn) The compliance C values forthe three types of waveforms seem to be opposite to the otherparameters, but the order of the parameters becomes the same for all thewaveform shapes, when inverse values, 1/C, of the compliance values areused. The relationship between the dynamic parameters and the threewaveform types were subjected to the T-test, and the results werestatistically significant with uncertainty of less than 0.05.

[0361] Chapter 3-1: Diagnostic Apparatus on the Basis of the WaveformShapes

[0362] Next, the diagnostic apparatus (i) of the third embodiment willbe explained. This apparatus computes the distortion from themeasurement data of the pulse waveforms, decides the shape on the basisof the distortion and performs diagnosis on the basis of the waveformshapes.

[0363]FIG. 27 is a block diagram showing the structure of this apparatus(i). The reference numeral 311 refers to a pulse wave detection device,and FIG. 28 illustrates the method of detection. In FIG. 28, S1 refersto a pressure sensor for detecting the radial arterial waveforms of anexaminee. The numeral S2 refers to a cuff belt worn on the upper arm tomeasure the blood pressure. The pulse wave detection device 311 modifiesthe radial arterial waveforms with blood pressure, and outputs theresults as analogue electrical signals. In FIG. 27, the numeral 313refers to an A/D converter to covert the analogue signals outputted bythe pulse wave detection device 311 to digital signals. The numeral 314refers to a distortion calculator comprising a Fourier analyzer 315 anda distortion computation device 317. The Fourier analyzer 315 includesmicrocomputers and others, and the analytical programs for Fourieranalysis are stored in memories such as ROM. The Fourier analyzer 315analyzes the digital signals outputted from the A/D converter 313, andoutputs the amplitude Q 1 of the fundamental waveform, the amplitude Q 2of the second harmonics, . . . and the amplitude Qn of the nthharmonics. The value of n is determined suitably depending on theamplitude of the nth harmonic distortion.

[0364] The distortion calculator 317 calculates the value of thedistortion based on the outputted amplitudes Q 1 , Q 2 and Qn. Thedistortion value d is obtain from the expression:$d = \frac{\sqrt{Q_{2}^{2} + Q_{3}^{2} + \ldots \quad + Q_{n}^{2}}}{Q_{1}}$

[0365] The numeral 319 refers to a waveform shape analyzer whichdetermines the shape of the waveforms based on the distortion factor doutputted from the distortion calculator 314 such that:

[0366] 1.161>d>0.960 defines the Hua mai type;

[0367] 0.960>d>0.854 defines the Ping mai type; and

[0368] 0.798>d>0.670 defines the Xuan mai type.

[0369] The waveform shape analyzer 319 either outputs the results of thedetermination of the waveform type according to the above definitions,or displays or prints on an output device 321 that a waveform type isindeterminate.

[0370] In this case, the diagnostic apparatus presented in Chapter 1 maybe used for diagnostics by storing data (potential illness) relating thewaveform shapes to the conditions of the living body in the knowledgedata base 26, and reading out data (i.e. diagnosis) to correspond withthe results obtained from the waveform shape analyzer 319 of the thirdembodiment.

[0371] Chapter 3-2: Diagnostic Apparatus on the Basis of the CirculatoryParameters Next, the diagnostic apparatus (ii) of the third embodimentwill be explained. This apparatus computes the distortion from themeasurement data of the pulse waves; computes the circulatory parametersby the distortion; and performs diagnosis on the basis of theseparameters.

[0372] The apparatus (ii) is shown in FIG. 29. In FIG. 29, thosecomponents which are the same as in the apparatus (i) shown in FIG. 27are given the same reference numerals, and their explanations areomitted.

[0373] The numeral 323 refers to a circulatory dynamic parametercalculator, and computes the values of the proximal section resistanceRc, distal section resistance R_(p), the momentum L and the compliance Con the basis of the values of the distortion factor d calculated by thedistortion calculator 314. The circulatory dynamic parameters arecalculated from the following expressions.

R _(c)=58.68·d ^(−0.394)

R _(p)=2321·e ^(−0.615) d

L=162.8·e ^(−2.585) d

C=10⁻⁴ −1.607+3.342·d

[0374] The units are the same as in the previous expressions in Chapter2-1-1.

[0375] As explained above, by utilizing the relationship equations, itwill be possible to compute the circulatory dynamic parameters withoutusing the pulse wave analysis apparatus described in Chapter 2. It isobvious that the computed dynamic parameters are also applicable to thefirst embodiment described in Chapter 1.

[0376] The dynamic parameter calculator 323 determines the waveform typebased on the dynamic parameters.

[0377] In this apparatus (ii), the Hua mai type is defined by:

28.878<R_(c)<65.218

1005.4<R_(p)<1358.5

7.647<L<12.994 and

1.476×10⁻⁴<C<2.584×10⁻⁴,

[0378] the Ping mai type is defined by:

55.543<R_(c)<128.531

1158.2<R_(p)<1614.8

11.810<L<21.018

[0379] and

1.076×10⁻⁴<C<1.698×10 ⁻⁴,

[0380] the Xuan mai type is defined by:

164.958<R_(c)<287.228

1332.0<R_(p)<1834.0

22.157<L<32.943

[0381] and

0.612×10^(−4<C<)1.026×10^(−4.)

[0382] The dynamic parameter calculator 323 outputs the results of thedetermination through an output device 321.

[0383] It is obvious that the defined waveform types as parameters arealso applicable to the first embodiment.

[0384] Chapter 3-3: Diagnostic Apparatus on the Basis of Waveform Shapesand Parameters

[0385] Next, the apparatus (iii) of the third embodiment will beexplained. This apparatus computes the distortion from the measurementdata of the pulse waves; by the distortion, computes the circulatoryparameters and determines the waveform shape type; and performsdiagnosis on the basis of these parameters and the shapes.

[0386] This apparatus (iii) is shown in FIG. 30. In FIG. 30, thosecomponents which are the same as in the apparatus (i) or (ii) shown inFIG. 27 or 29 are referred to by the same reference numerals, and theirexplanations are omitted.

[0387] The reference numeral 325 refers to a comprehensive analyzer, andperforms pulse wave analysis based on the entire results of the waveformshape analyzer 319 and the dynamic parameter calculator 323. Forexample, the waveform results by the waveform analyzer 319 and theparameters determined by the dynamic parameter calculator 323 may bestored in a memory table in the comprehensive analyzer 325 for its use.The output results may be one of the three waveform shape types, or thenames of the illness associated with that waveform. The output device321 displays or prints the results outputted from the waveform shapeanalyzer 319, from the dynamic parameter calculator 323, from thecomprehensive analyzer 325 and others. The user of the apparatus such asdoctors and others are thus able to obtain the diagnostic informationregarding the examinee.

[0388] Alternatively, a diagnosis may be performed in terms of thewaveforms parameters in the first embodiment, determined on the basis ofthe waveform shape obtained from the waveform shape analyzer 319 and thecirculatory dynamic parameters computed by the dynamic parametercalculator 323.

[0389] In the third embodiment, the distortion factor d may be definedin terms of the mathematical expression$\frac{Q_{2} + Q_{3} + \ldots \quad + Q_{n}}{Q_{1}},$

[0390] or it may be defined in other ways, but the same relationshipwill be obtained. For example, the distortion factor d may be obtainedby a method illustrated in FIG. 41. In this method, the pulse waves areinputted into a low-pass filter 351 and a high-pass filter 354 to outputa low frequency component v1 and a high frequency component v2. Theoutputted signals v1, v2 are passed through rectifier circuits 352, 355and passed through smoothing circuits (normally used LPF) 353, 356 toobtain direct current signals w1, w2. The DC signals w1, w2 areforwarded to the division circuit 357 to obtain a value of thedistortion factor d=w2/w1.

[0391] Chapter 4: Stress Level and Physiological Age EvaluationApparatus

[0392] Recently, stress and fatigue has come to be one of the maincauses of adult sickness, and so called death due to overwork. If theconditions of stress and fatigue can be grasped, then throughappropriate precautionary measures taken at an early stage, theprogression of the adult disease, and sudden death etc. can beprevented.

[0393] Presently there are few examination methods which can detectstress, fatigue and often physiological and psychological problem of ahuman body. Moreover, of these few examination methods, there are nonewhich enable simple examination. For example, some methods measure thecontents of catecholamine or cortisol included in the blood or urine, asan indication of physiological stress. However with these methods, ablood sample or a special assay method is necessary. The methods arethus not simple methods which can be made every day. Moreover, there isa method which measures the urine concentration of adrenocorticalhormone metabolism production as an indication of stress. However, thismethod also cannot be considered simple since a urine sample isrequired. Moreover, the reliability as an examination method has yet tobe established. The so called Claris system diagnostic questionnaire ofthe B&M company was an established method of measuring psychologicalstress. However this diagnostic questionnaire had 81 question items,thus imposing a heavy burden on the patient or the diagnostician at thetime of questioning. Additionally, there has been a need for a devicewhereby one can easily perform of his own physiological age as well asstress level.

[0394] In view of the problems described above, the present inventorsselected the peak points of the waveforms to be representative of thewaveform parameters to be used in the determination of psychosomaticstress levels and physiological age, and produced a diagnostic apparatusof a fourth embodiment.

[0395] The application of the diagnosis of the present invention is notlimited to the stress level or physiological age, further the parametersare not limited to disclosed waveform parameters used to the diagnosisin the embodiment of the invention. For other diagnoses, some suitablediagnostic apparatus can be developed using the same approach aspresented in the following.

[0396] The peak points of the waveforms obtained by this diagnosticapparatus can be applicable to the first embodiment for the waveformparameters.

[0397] In this Chapter, the diagnostic apparatus according to a fourthembodiment of the present invention will be explained.

[0398] Chapter 4-0: Pre-examinations

[0399] The present inventor carried out the following pre-examinationswhen designing the device for stress evaluation.

[0400] Chapter 4-0-1: Characteristics for Substitutional Parameters Inorder to carry out the stress evaluation without imposing a heavy burdenon the examiner or the procedure, substitute parameters for stressparameters such as blood plasma catecholamine values, which reflect thestress level are necessary. The present inventor observed that waveformsof pulse waves change, due to physiological stress, physiological ageand psychological stress, and selected waveforms of pulse waves ascandidates for parameters for use in stress evaluation. In the process,the radial arterial pulses of 53 examinees was measured, and thefollowing information, i.e., the peak points (inflection points) ofpulse waveform was collected as characterizing waveform parameters toanalyze the problem.

[0401] (a) The period T₆, which represents the time for one pulsationcycle from the rise of one pulsation (in the following, the time of thisrise is referred to as the pulse wave initiation time) and the nextpulsation rise.

[0402] (b) The blood pressure values y 1 ˜y 5 , representing a maximumpoint P 1 , a minimum point P 2 , a maximum point P 3 , a minimum pointP 4 , and a maximum point P 5 appearing successively in the pulse waves.

[0403] (c) The elapsed periods T 1 ˜T 5 , corresponding to time periodfrom the pulse wave initiation time to the appearance of the respectivepoints P 1 ˜P 5.

[0404] Refer to FIG. 42 for the above.

[0405] Moreover, the present inventor observed that conscious symptomsappear when the stress level became high, and measured psychosomaticfatigue level using the psychosomatic fatigue level diagnosticquestionnaire shown in FIG. 43. The questions in the diagnosticquestionnaire were to ascertain whether the patients was conscious ofthe various symptoms which are prominent at high stress levels. Theexaminee selected one of; never, sometimes, often, or always as a replyto the questions. Here the points for the respective replies were:$\begin{matrix}\begin{matrix}{{never}\quad {at}} & {\quad^{``}{0^{"};}} \\{{sometimes}\quad {at}} & {\quad^{``}{1^{"};}}\end{matrix} \\\begin{matrix}{{often}\quad {at}} & {\quad^{``}{2^{"};}} \\{{and}\quad {always}\quad {at}} & {\quad^{``}3^{"}.}\end{matrix}\end{matrix}$

[0406] With an affirmative reply to a question, that is to say, a higherreply level for the degree of consciousness of the symptom,proportionally higher points were obtained. The total points obtainedfor the patient's selected answers become the psychosomatic fatiguelevel M.

[0407] Chapter 4-0-2: Reference Values for Stress Levels

[0408] The blood plasma catecholamine value has been recognized in thepast as a stress index of physiological stress. Therefore the bloodplasma adrenaline densities AD (ng/ml), and the blood plasma noradrenaline densities NA (ng/ml), in the blood of 53 examinees weremeasured, and became the reference value for the physiological stress ofeach of the examinees.

[0409] For the psychological stress, a diagnostic questionnaire with 81headings (B & M Claris System) was made for each of the examinees. Theresults of this became the reference value MS for the psychologicalstress level of the examinee.

[0410] Chapter 4-0-3: Correlation Analysis

[0411] A correlation analysis was made among the respective parametersobtained for each examinee in the above Chapter 4-0-1, and in thephysiological stress level and psychological stress level obtained inthe above Chapter 4-0-2.

[0412] (1) Physiological Stress

[0413] Initially, in making a correlation analysis of the blood plasmacatecholamine value, and the waveform parameters, the following equationwas obtained as a relationship equation with a high correlationcoefficient “r”,

NA(ng/ml)=−0.44(T ₅ −T ₁)+1.07  (51)

[0414] with main correlation coefficient r=0.44 (probability p<0.000001,F value=25.42).

[0415] It was confirmed that with this equation as an indication ofphysiological stress level, the blood plasma nor adrenaline value couldbe estimated on the basis of the waveform parameters T 1 and T 5 . Inthe present embodiment, the physiological stress level is calculated bycalculating out the right side in equation (51).

[0416] In making a correlation analysis including not only the waveformparameters but also the psychosomatic fatigue level M, the followingrelationship equation was obtained, $\begin{matrix}{{{NA}\left( {{ng}/{ml}} \right)} = {{0.46M} + {0.24\frac{y_{1}}{T_{1}}}}} & (52)\end{matrix}$

[0417] with r=0.51, (p<0.000001, F=12.47).

[0418] Also including the psychosomatic fatigue level M as a parameterin this way was confirmed to give a more accurate value for theestimation of the physiological stress level. In the present example,when it is possible to obtain the psychosomatic fatigue level M, thephysiological stress level is calculated by calculating the right sidein equation (52).

[0419] (2) Psychological Stress

[0420] In making a correlation analysis of the reference value MS forthe psychological stress, the waveform parameters and the psychosomaticfatigue level M, the following equation was obtained as a relationshipequation with a high correlation coefficient. $\begin{matrix}{{MS} = {{0.45M} + \frac{{0.29T_{4}} - T_{1}}{T_{6}} - 14.83}} & (53)\end{matrix}$

[0421] with r=0.56, (p<0.000001, F=21.61).

[0422] In the present embodiment, the psychological stress level iscalculated by carrying out the right side calculation in equation (53).

[0423] (3) Physiological Age

[0424] When the correlation relationship between the age Y of theexaminee, and the waveform parameters was investigated, it was foundthat a correlation coefficient existed between both. $\begin{matrix}{Y = {{33.74\quad T_{5}} - T_{4} + {61.64\frac{T_{1}}{T_{6}}} - {8.0678\frac{T_{5} - T_{4}}{T_{6}}} + 33.324}} & (54)\end{matrix}$

[0425] with r=0.56, (p<0.00000, F=12.609).

[0426] Chapter 4-1: Diagnostic Apparatus (i)

[0427] Next, the diagnostic apparatus (i) in accordance with the fourthembodiment of the present invention will be explained. This apparatusperforms diagnosis of physiological and psychological stress levels; andphysiological age of the examinee on the base of the inputted parametersof his pulse waveforms.

[0428] Chapter 4-1-1: Structure of the Diagnostic Apparatus (i)

[0429]FIG. 44 shows the structure of the apparatus according to theapparatus (i). In this Figure, numeral 401 indicates a micro-computer,for controlling the operation of the respective components of theapparatus, and for carrying out a diagnosis of the physiological stresslevel, psychological stress level and physiological age according to theabove equations (52), (53) and (54). Numeral 402 indicates a keyboardwhich is used as an input means for command of the micro-computer 401,and for the input of parameters for diagnosis. Numeral 403 indicates aFDD (floppy disk drive unit) provided as a parameter input means in thecase of a large number of examinees. The examiner installs a FD, onwhich is stored the parameters for the various examinees, into the FDD403. Consequently, the parameters for all examinees can be transferredto the micro-computer 401 as a batch. The means for storage of theparameters to be inputted to the apparatus is not limited to a magneticdisk such as a floppy disk, and disks such as optical magnetic disks maybe used. Numeral 404 indicates a display apparatus such as a CRT, whichdisplays the messages and stress level diagnosis results output from themicro-computer 401, for viewing by the examiner. Numeral 405 indicates alarge capacity storage unit provided for storing the diagnosis resultsof the stress levels etc., and the parameters for use in the diagnosis,serially for each examinee. Numeral 406 indicates a printer for theoutput of diagnosis results such as stress level.

[0430] Chapter 4-1-2: Operation of the Diagnostic Apparatus (i) Onswitching on the power supply to the diagnostic apparatus (i), aninitialization process is carried out by the micro-computer 401, and amenu screen for prompting the selection of either the keyboard 402 orthe FDD 403 for carrying out the parameter input, appears on the displaydevice 404. The examiner inputs a command from the keyboard, and selectsthe desired input configuration.

[0431] (1) Parameter Input

[0432] When the keyboard input configuration is selected, the examinerinputs successively by way of keyboard 402, the identificationinformation for the examinee, the parameters necessary for evaluation,that is to say the waveform parameters and psychosomatic fatigue levelobtained by the above fatigue level diagnostic questionnaire, and theyear, month and day of collection of these parameters. This informationis successively inputted to the buffer memory inside the micro-computer401.

[0433] On the other hand, when the FDD input configuration is selected,the examiner inserts into the FDD 403, the floppy disk on which isstored the identifying information for each examinee, the parametersnecessary for evaluation of stress level etc., and the year, month andday of collection of these parameters, and inputs a command from thekeyboard 402 directing input from the floppy disk to the buffer memory.As a result, the information corresponding to each of the examinees onthe FD is input sequentially from the FDD 403 to the buffer memoryinside the micro-computer 401.

[0434] (2) Diagnosis of Stress Level (and the like)

[0435] On completion of input of the above mentioned parameters, theparameters in the buffer memory for diagnosis of the stress of eachexaminee, are substituted into the above mentioned equations (52), (53)and (54) to obtain the physiological stress level, psychological stresslevel and physiological age for each of the examinees. The resultantphysiological and psychological stress levels and physiological age foreach of the examinees are stored temporarily in the buffer memory.Furthermore, the stress level for each of the examinees and theparameters used for calculation of the stress levels are displayed foreach examinee on the display device 404. (3) Storage of DiagnosisResults

[0436] On completion of the diagnosis, the examiner directs storage ofthe diagnosis results from the keyboard 402, so that the information inthe buffer memory corresponding to each of the examinee, is successivelywritten to the large capacity storage unit 405. Then, more specifically,with the present apparatus, the diagnosis results such as stress level,and the information used in the diagnosis are partitioned for eachexaminee, and stored. The information related to the respectiveexaminees that is read from the buffer memory, is added to the end ofthe previously stored information corresponding to the respectiveexaminees in the large capacity storage unit 405.

[0437] (4) Print out of Diagnosis Results

[0438] When the examiners inputs from the key board 402, the command foroutput of the diagnosis results, the micro-computer 401 sends theidentification information and stress levels for each of the examineeswhich are stored in the buffer memory, to the printer 406 for print out.Furthermore, if the examiner inputs identification information for aspecific examinee, together with a command for a time series display ofthe stress levels, the micro-computer 401 reads from the large capacitystorage unit 405, the stress levels obtained by a predetermined numberof previous diagnosis corresponding to the selected examinee, and thecollection year month and day of the parameters used in the stressdiagnosis. The micro-computer 401 then generates data for printing agraph showing the time change of stress level, and sends this to theprinter 406. As a result, the printer 406 prints out the stress leveltime changes for the selected examinee.

[0439] Chapter 4-2: Diagnostic Apparatus (ii)

[0440] Next, the diagnostic apparatus (ii) in accordance with the fourthembodiment.

[0441] This apparatus (ii), adds to the apparatus (i) described inChapter 4-1, a means for measuring the pulse wave of the examinee, and ameans for detecting the waveform parameters from these pulse waves,thereby enabling the collection of parameters from the examinee, andstress evaluation to be carried out simultaneously.

[0442] Chapter 4-2-1: Structure of the Diagnostic Apparatus (ii)

[0443]FIG. 45 is a block diagram showing the structure of a diagnosticapparatus. In this figure, components corresponding to those of theapparatus (i) explained in Chapter 4-1 are indicated by the same symbolsand description is omitted.

[0444] In FIG. 45, numeral 411 indicates a pulse wave detectionapparatus, which detects the radial pulse waveform by means of apressure sensor attached to the examinee's wrist (not shown on thefigure), and outputs a pulse wave signal (analog signal). Numeral 412indicates a parameter sampling section, which processes signals undermicro-computer 401 control, to extract waveform parameters necessary fordiagnosis of the stress level, from the pulse wave signal output fromthe pulse wave detection apparatus 411. Numeral 413 indicates a mouse,which is connected to the micro-computer 401, and acts as a designationdevice when manually designating the waveform parameter, without usingthe parameter sampling section 412.

[0445] The following is a description of the construction of theparameter sampling section 412, with reference to FIG. 46. In FIG. 46,numeral 501 indicates an A/D (analog/digital) converter which convertsthe pulse wave signal output by the pulse wave detector 411, into adigital signal, in accordance with a sampling clock f of a fixed period,and outputs this. Numeral 502 indicates a low pass filter which carriesout processing to eliminate components of the successively outputdigital signal from the A/D converter 501, that are above apredetermined cut-off frequency. The result is successively outputted aswaveform values W. Numeral 503 indicates a waveform memory comprising aRAM (random access memory) which successively stores the waveform valuesW supplied by way of the low pass filter 502. Numeral 511 indicates awaveform address counter which counts the sampling clock f during theperiod when the waveform collection directive START from themicro-computer 401 is outputted. The count results are output aswaveform addresses ADR1 into which the waveform values W are to bewritten. Numeral 512 indicates a selector which selects the waveformaddresses ADR1 output by the waveform address counter 511, when themanual output mode signal MAN is not outputted, and supplies these tothe address input terminal of the waveform memory 503; and selects theread addresses ADR4 outputted by the microcomputer 401, when the manualoutput mode signal MAN is outputted, and supplies these to the addressinput terminal of the waveform memory 503.

[0446] Numeral 521 indicates a differentiating circuit which computesthe time differentials of the waveform values W which are successivelyoutput from the low pass filter 502, and outputs these. Numeral 522indicates a null cross detection circuit which outputs a null crossdetection pulse Z when the time differential of the waveform value W is“0” due to the waveform value W being a maximum value or a minimumvalue. Numeral 523 indicates a peak address counter which counts thenull cross detection pulse Z during the period when the waveformcollection directive START from the micro-computer 401 is outputted. Thecount results are outputted as peak addresses ADR2. Numeral 524indicates an average movement computation circuit which computes, up tothe present time point, the mean value of the time differential valuesof a predetermined number of previous waveform values W, which areoutputted from the differentiating circuit 521, and outputs the resultas slope information SLP which shows the slope of the pulse waves upuntil the present time point. Numeral 525 indicates a peak informationmemory (to be discussed later) for storing peak information.

[0447] The micro-computer 401 carries out the following control stepsbased on the information inputted from the respective elements describedabove.

[0448] (1) Peak Information Editing

[0449] The differentiation circuit 521, and the null cross detectioncircuit 522 inside the parameter sampling section 412, obtain thefollowing listed information for each detection of a waveform peakpoint. This information is written to the peak information memory 525 aspeak information.

[0450] Contents of the Peak Information

[0451] (1)-1: Waveform Value Address ADR1:

[0452] This is the write address ADR1 which is output from the waveformaddress counter 511 at the time point when the waveform value Woutputted from the low pass filter 502, becomes a maximum or minimumvalue. That is to say, the write address in the waveform memory 503 forthe waveform value W corresponding to the maximum or minimum value.

[0453] (1)-2: Peak classification B/T:

[0454] This is information which indicates whether a waveform value Wwritten to a waveform value address ADR1 is a maximum value T (Top), ora minimum value B (Bottom).

[0455] (1)-3: Waveform Value W:

[0456] This is the waveform value corresponding to the maximum value orthe minimum value.

[0457] (1)-4: Stroke STRK:

[0458] This is the change portion of the waveform value, from theimmediately preceding peak value to the present peak value.

[0459] (1)-5: Slope information SLP:

[0460] This is the mean value of the time differential of thepredetermined number of previous waveform values up until the presentpeak value.

[0461] On the stress level diagnosis, the microcomputer 401 shifts tothe following operational mode.

[0462] (a) Automatic Diagnosis Mode

[0463] Reads the storage contents of the peak information memory 525,generates the waveform parameters, and carries out the stress leveldiagnosis in a similar manner to that of the first working diagnosticapparatus (i).

[0464] (b) Manual Designation Mode Displays the waveform stored in thewaveform memory 503 on the display device 404, detects the waveform peakpoint designated by operator mouse operation, and carries out thecomputation of the waveform parameters and diagnosis of the stresslevel, on the basis of the results.

[0465] Chapter 4-2-2: Operation of the Diagnosis Apparatus (ii)

[0466] The following is a description of the operation of the Diagnosisapparatus.

[0467] (a) Automatic Diagnosis Mode

[0468] (a)-(1) Collection of Waveform and Peak Information

[0469] Initially, on input by way of keyboard 402 of a command to obtainthe stress level, the micro-computer 401 outputs a waveform collectiondirective START, and releases the reset of the waveform address counter511 and the peak address counter 523, in the parameter sampling section412.

[0470] As a result, the waveform address counter 511 starts counting thesampling clock f, and the count value is supplied via the selector 512,to the waveform memory 503 as a waveform address ADR1. The radialarterial pulse waveform detected by the pulse wave detector 411 is inputto the A/D converter 501, and converted sequentially into a digitalsignal according to the sampling clock f, and then outputtedsequentially as waveform values W, via the low pass filter 502. Thewaveform values W outputted in this way are supplied sequentially to thewaveform memory 503, and written to a memory area designated by thewaveform address ADR1 at that time point. By means of the aboveoperation, one row of waveform values W corresponding to the radialpulse waveform illustrated in FIG. 48, are stored in the waveform memory503.

[0471] Detection of the peak information, and writing to the peakinformation memory 525 is carried out in parallel with the aboveoperation as described below.

[0472] Initially the time differential of the waveform value W outputfrom the low pass filter 502, is computed by the differentiating circuit521. This time differential is then input to the null cross detectioncircuit 522 and the mean movement calculating circuit 524. The meanmovement calculating circuit calculates the mean value (that is to saymean movement value) of the predetermined number of previous timedifferentials for each time differential value of this type of waveformvalue W supplied, and the calculated result is output as slopeinformation SLP. Here, when the waveform value W is increasing or has amaximum condition after increasing, a positive value is outputted as theslope information SLP, while when decreasing or with a minimum valueafter decreasing, a negative value is output as the slope informationSLP.

[0473] On output of the waveform value W corresponding to the maximumpoint Pi as shown in FIG. 48, from the low pass filter 502, a “0” forthe time differential is outputted from the differentiating circuit 521,and a null cross detection pulse Z is outputted from the null crossdetection circuit 522.

[0474] As a result, the micro-computer 401 fetches, the waveform addressADR1 being the count value of the waveform address counter 511, thewaveform value W, the peak address ADR2 being the count value of thepeak address counter (in this case ADR2=“0”), and the slope informationSLP, for that time point. Due to the output of the null cross detectionsignal Z, the count value ADR2 of the peak address counter 523 becomes“2”.

[0475] Subsequently, the micro-computer 401 creates a peakclassification B/T based on the symbol of the fetched slope informationSLP. In this case, since positive slope information is outputted at thetime point when the waveform value W for the maximum value Pi isoutputted, the micro-computer 401 sets the value of the peak informationB/T to one corresponding to a maximum value. The micro-computer 401 thendesignates the peak address ADR2 (in this case ADR2=0) as fetched fromthe peak address counter 523, as the write address ADR3, and writes thewaveform value W, the waveform address ADR1 corresponding to thewaveform value W, the peak classification B/T, and the slope informationSLP, into the peak information memory 525 as first peak information. Inthe case of writing the first peak information, since there is no peakinformation immediately prior to this, then the creation and writing ofstroke information is not carried out.

[0476] Subsequently, on output of a waveform value W corresponding tothe minimum point P 2 as shown in FIG. 48, from the low pass filter 502,a null cross detection pulse Z is outputted in a similar manner to theabove, and the write address ADR1, waveform value W, peak address ADR2(=1), and the slope information SLP (<0) are fetched by themicro-computer 401. Subsequently, the micro-computer 401 determines thepeak classification B/T (in this case bottom B) based on the slopeinformation SLP in a similar manner to the above. Moreover, themicro-computer 401 supplies an address that is one smaller than the peakaddress ADR2, to the peak information memory 525 as a read out addressADR3, and reads out the first written waveform value W. Then, themicro-computer 401 calculates the difference between the waveform valueW fetched this time from the low pass filter 502, and the first waveformvalue W read from peak information memory 525, to obtain the strokeinformation STRK. The peak classification B/T, and stroke informationSTRK obtained in this way are written together with other informationADR1, W, slope information SLP, as second peak information, to an areacorresponding to the peak address ADR3=1 of the peak information memory525. The subsequent operations for when the peak points P 3 , P 4 etc.are detected, are carried out in a similar manner.

[0477] Then after the elapse of a predetermined period, the output bythe micro-computer 401, of the waveform collection directive START isstopped, terminating collection of the waveform values W and peakinformation.

[0478] (a)-(2) Waveform Parameter Sampling

[0479] Prior to waveform parameter extraction, the micro-computer 401carries out a process to specify information corresponding to waveformsof one wave length, for collecting the waveform parameters from amongstthe various information stored in the peak information memory 525.

[0480] Initially the slope information SLP and stroke information STRKcorresponding to respective peak points P 1 , P 2 etc. are successivelyread out from the peak information memory 525. After this, strokeinformation corresponding to a positive slope (that is to saycorresponding to slope information SLP with a positive value) isselected from amongst the respective stroke information STRK. Then, fromamongst this stroke information, a predetermined number of higher rankstroke information having large values is further selected. After this,one corresponding to a middle values is selected from amongst theselected stroke information STRK, and the stroke information is obtainedfor the rising part of the pulse wave of one wave length portion whichis to be subjected to waveform parameter extraction, for example therising portion indicated by symbol STRKM in FIG. 48. Subsequently thepeak address one prior to the peak address of the said strokeinformation is obtained. That is to say, the peak address of the startpoint P 6 of the pulse wave of the one wave length portion which is tobe subjected to waveform parameter extraction.

[0481] Next the micro-computer 401 refers to the respective peakinformation in the peak information memory 525, which corresponds to thepulse wave of one wave length portion, and computes respective peakinformation for substitution into the beforementioned computationalequations (51)˜(54). For example the following information.

[0482] y 1 : y 1 is the waveform value y 1 corresponding to peak point P7.

[0483] T 1 : T 1 is calculated by subtracting the waveform addresscorresponding to peak point P 6 from the waveform address correspondingto peak point P 7 , and multiplying the result by the period of thesampling clock Φ.

[0484] T 4˜T 6 : T 4 ˜T 6 are calculated in a similar manner to T 1 ,based on the difference between the waveform addresses of the respectivepeak points.

[0485] The respective parameters obtained in this way are stored in thebuffer memory.

[0486] (b) Manual Directive Mode

[0487] With the diagnostic apparatus (ii), it is possible to set amanual directive mode (a) using keyboard 402 operation, in addition tothe above automatic diagnosis mode. When this manual directive mode isset, the examiner can designate by operation of a mouse, the peak pointsof the pulse waves necessary for the calculations of the waveformparameters. That is to say, according to the following.

[0488] In the manual directive mode, after outputting the waveformcollection directive START for a predetermined time, the micro-computer401 outputs a manual mode signal MAN. Then, read addresses ADR4increasing successively from “0” are output by the micro-computer 401,and supplied to the waveform memory 503 by way of the selector 512.Radial pulse waveforms stored in the waveform memory 503 are thus readout and displayed on the display device 404.

[0489] Through operation of the mouse 413, the examiner moves the cursorposition on the display device 404, and successively indicates the firstpoint and last point of the pulse wave, and the various maximum andminimum points of the pulse wave with a click input. The micro-computer401 detects the mouse operation, reads from the waveform memory 503digital signals corresponding to the first point and last point, and therespective maximum and minimum points of the pulse wave designated bythe examiner, and extracts the necessary waveform parameters (see theabove equation (52) and (53)) from the read out information, and storesthese in the buffer memory.

[0490] (c) Psychosomatic Fatigue Level Input

[0491] On completion of the waveform parameter collection through eitherof the above (a) or (b) mode, the micro-computer 401 displays thepsychosomatic fatigue level diagnostic questionnaire shown in FIG. 43 onthe display device 404 in accordance with the keyboard or mousedirective of the examiner. The examiner then makes a question diagnosisof the examinee corresponding to the displayed questions diagnosistable, and inputs the examinees response to the micro-computer 401 bymouse 413 operation. Here the question diagnosis may be a dialogue formof input. That is to say, each question on the diagnostic questionnaireis displayed one at time, or outputted as a voice, and the answercorresponding to this can take the format of examinee input by akeyboard or the like, to the micro-computer 401. The micro-computer 401calculates the psychosomatic fatigue level on the basis of the inputanswers, and writes the result into the buffer memory.

[0492] All of the information necessary for this stress evaluation isarranged in the buffer memory as above. The micro-computer 401 makes astress level diagnosis based on the information stored in the buffermemory, and thereafter the results are outputted and stored under thedirective of the examiner in a similar manner to the apparatus (i) inexplained in Chapter 4-1.

[0493] Chapter 4-3: Diagnostic Apparatus (iii)

[0494] Next is a description of a diagnostic apparatus (iii). Thisstress level diagnostic apparatus has a color display device (not shownin the figure) as a stress level display means, in addition to theconstruction to the apparatus (ii) explained in Chapter 4-2. Themicro-computer 401 in this apparatus, after calculating thephysiological stress level and the psychological stress level,determines the display color according to the illustrated table of FIG.49, and displays this on the color display unit.

[0495] The physiological stress level, psychological stress level andphysiological age are obtained and these may be color displayed. In thiscase, rather than the two dimensional table shown in FIG. 49, a threedimensional display defining colors corresponding to the respectivecombinations of physiological stress level, psychological stress leveland physiological age, can be used to determine the display color.

[0496] With the present apparatus, the combined stress levels of thephysiological stress level and psychological stress level are indicatedby the display color of the color display device. Hence even the generalpublic, who have no judgment basis with respect to numerical values ofstress level, can easily confirm their own stress level.

[0497] With the above apparatus, the examinee can use it as an automaticsystem for diagnosing his/her own stress level, without the need for aexaminer such as a doctor.

[0498] Chapter 4-4: Variation of the Fourth Embodiment

[0499] The fourth embodiment is not limited to the above diagnosticapparatuses (i) to (iii). For example, a number of variations such asgiven below are also possible.

[0500] Apparatus (iv)

[0501] With the above apparatuses, both the waveform parameter and thepsychosomatic fatigue level are used as parameters, and both thephysiological stress and the psychological stress diagnosis performed.However, it is also possible to have a construction wherein only thephysiological stress or physiological age are evaluated based on onlythe waveform parameter according to equation (51) or equation (54). Inthis case, since the effort of input of the psychosomatic fatigue levelis omitted, use of the apparatus is simplified.

[0502] Apparatus (v)

[0503] In the above respective apparatuses, the stress level isperformed of diagnosis on the basis of the examinees radial arterialpulse wave. However, the arterial pulse wave can be measured atlocations from the radial portion to the finger portion, and the stresslevel diagnosis performed on the basis of this arterial pulse wave.

[0504] Apparatus (vi)

[0505] In the above apparatus (iii), a structure was adopted wherein thestress level etc. was made visible by means of display colors. However,the stress level display means is not limited to this. For apparatus, ina situation wherein the examinee recognizes the stress level in a visualsense, the stress level may be represented by the shading of the displaycolor. It is also possible to display character information describingthe stress level. Moreover, the display is not limited to visual methodsof expression, and it may be possible to have a method wherein thestress level is expressed by appealing to a sense of hearing. Forexample, the pitch, volume, and tone of the sound may be changeddepending on the stress level etc., and played to the examinee. Also, avoice output explaining the evaluation results of the stress level etc.is possible. Music may be provided corresponding to the stress leveletc., such as bright music when the stress level is low and gloomy musicwhen the stress level is high.

[0506] In Chapter 4, the apparatus for performing diagnosis for thestress level and the physiological age were presented. Utilizing themethod used in the above apparatus, a diagnostic apparatus for othersubjects can be structured. In this case, the waveform parameters whichhave the highest correlation for the diagnostic subject may be used. Forexample, the dynamic circulatory parameters described in Chapter 2, thepulse waveform spectrum described in Chapter 1, and so on, may be usedas waveform parameters.

[0507] The means for obtaining the wavefom parameter used to diagnose isnot limit to the above apparatuses, and may be selected so as to befavorable to obtaining required parameter.

[0508] For example, there are the two methods to obtain the circulatorydynamic parameters; using the electrical model in Chapter 2, andcomputing the distortion factor of pulse waveform in Chapter 3. Eitherof the two methods may be favorably selected by considering theoperational speed, accuracy, and so like for requirement.

[0509] As explained, diagnosis for the stress level can be accuratelyperformed considering the psychosomatic fatigue level. Similarly, thereare cases when a diagnosis may be more accurately performed by thetaking the conscious symptom of the examinee into consideration. In thiscase, by adding inputting means for inputting conscious symptoms in thediagnostic apparatus, diagnosis may be performed based on both theinputted conscious symptom and waveform parameter of the pulse wave.

[0510] Moreover, depending on the diagnostic subjects, there are caseswhen it is wanted not only simply the name of disease but also theseriousness of the disease and outputting the computed degree. In such acase, using visual data (color, density, character and so on) and/or theaudio data (music, voice and so on), diagnostic apparatus may expressand output the degree of seriousness of the disease (stress level in thediagnostic apparatus of the fourth embodiment). Diagnosis for eachpredetermined period my depends on the diagnosis contents.

[0511] Chapter 5: Pulse Wave Analyzing Apparatus for Analyzing Spectrumof Pulse Waves

[0512] Recently, pulse diagnosis has come to the public attention,resulting in intensified research to explore the health condition of thebody based on pulse waves. As general waveform analyzing techniques,there are techniques such as the FFT frequency analysis technique, andpulse wave analysis using this type of frequency analyzing technique isunder investigation.

[0513] A pulse waveform is not the same shape for all pulses, andchanges moment by moment. Moreover, the wavelength of each pulse wave isnot constant. A technique has been considered wherein a pulse wavehaving such chaotic (random) behavior is considered as a waveform havingan extremely long period, and subjecting it to a Fourier transformation.With such a technique, a detailed waveform spectrum can be obtained,however since the amount of computation becomes immense, the techniqueis not suited for use in rapidly obtaining the spectrum of pulse wavesoccurring moment by moment. If wave parameters representing thecharacteristics of the separate waves making up the pulse wave can beobtained continuously, then a much greater amount of informationrelating to a living body can be obtained. However a device to meet suchrequirements is presently not available.

[0514] Therefore, the one of objectives is to provide an apparatus foranalyzing the characteristic of each individual pulse waves rapidly.Furthermore, the fifth embodiment enables higher performance to beachieved in the various apparatuses presented in Chapter 1 to 5. In thefollowing, the pulse wave analysis apparatus according to the fifthembodiment will be explained.

[0515] Chapter 5-1: Pulse Wave Analyzer (i)

[0516] This analyzer performs computation of spectrum of pulse waves foreach pulsation.

[0517] Chapter 5-1-1: Structure of the Analyzer (i)

[0518]FIG. 50 shows the structure of a pulse wave analyzer according tothe fifth embodiment of the present invention. As is shown in the FIG.50, the pulse wave analyzer comprises a pulse wave detector 601, aninput unit 602, an output unit 603, a waveform sampling memory 604, afrequency analyzing unit 605 and a micro-computer 606 which controls allof these.

[0519] The pulse wave detector 601 comprises a strain gauge or the like,which can be pressed against an examinee's radial artery to detect thepressure, and output this as a pulse wave signal (analog signal). Theinput unit 602 is a device provided for command input such as a keyboardto the micro-computer 606. The output unit 603 comprises a printer,display devices and other. These devices come under the control of themicro-computer 606 and store, display etc. the pulse wave spectrumobtained from the examinee. The waveform sampling memory 604, undercontrol of the micro-computer 606, successively records the waveformsignals output from the pulse wave detector 601, and also extracts andstores information showing the change points in the pulse wave signal,that is to say the point of change from a pulse wave corresponding toone pulse to the pulse wave corresponding to the next pulse. The detailstructure of the waveform sampling memory 604 is same as the structureof the waveform sampling section 412.

[0520] The frequency analyzing unit 605 gives a repeating high speedplayback of the pulse wave signal stored in the waveform sampling memory604, for each pulsation, and obtains and outputs the spectrum making upthe pulse wave for each pulsation. FIG. 51 shows details of theconstruction. The pulse wave spectrum for each respective pulsationobtained from the frequency analyzing unit 605, is fetched by themicro-computer 606 and outputted from the output unit 603.

[0521] Chapter 5-1-1-1: Structure of the Waveform Sampling Memory 604The waveform sampling memory 604 may use the parameter sampling section412 with its signals and information shown in FIG. 46. The explanationof the waveform sampling memory 604 is omitted to avoid duplication. Itis maintained that the manual output mode signal MAN shown is replacedwith the select signal S11, and the numeral 401 is replaced with 606 forthe micro-computer. Chapter 5-1-1-2: Structure of the FrequencyAnalyzing Unit 605 Next is a detailed description of the construction ofthe frequency analyzing unit 605, with reference to FIG. 51. Thefrequency analyzing unit 605 receives, a waveform value WD for a pulsewave from the waveform memory 503 in the waveform sampling memory 604,by way of the micro-computer 606. The received waveform value WD isrepeatedly played back at high speed, and the frequencies are analyzedfor each pulse to compute spectrums for the pulse waves. Moreover, thefrequency analyzing unit 605 serially computes respective spectrumswhich construct the pulse waves, in the order of an initial basicspectrum of the pulse wave, following by the second harmonic wavespectrum, and so on.

[0522] When the first waveform value WD for the waveform of one pulsecomponent is output to the frequency analyzing unit 605, themicro-computer 606 outputs a synchronizing signal SYNC and an integer Nof the waveform value WD which is included in that pulse, and changesthe select signal S12. Furthermore, during the output of the waveformvalue WD for one pulse component, the micro-computer 606 successivelyoutputs write addresses ADR5 changing from “0” through to “N-1”,synchronously with the transfer of the respective waveform values WD.

[0523] Buffer memories 201, and, 202 are provided for storing thewaveform values WD outputted from the micro-computer 606. A distributor721 takes a waveform value WV for a pulse wave from the sampling memory604 supplied via the micro-computer 606, and outputs this to one ofbuffer memory 701 or 702 as designated by a select signal S12.Furthermore, a selector 722 selects from the buffer memories 201, 202,the buffer memory designated by the select signal S2, and a waveformvalue WH read from the selected buffer memory is outputted to the highspeed playback unit 730 (to be described later). Selectors 711 and 712select the write addresses ADR5, or the read addresses ADR6 (to bementioned later) generated by the high speed playback unit 730,according to the select signal S12, so that each is supplied to therespective buffer memory 701 and 702.

[0524] By switching control the above described distributor 721,selector 722, and 701 and 702 on the basis of the select signal S12,data is read from the buffer memory 702 and supplied to the high speedplayback unit 730, while writing data to buffer memory 701 and whilewriting data to the buffer memory 702, data is read from the buffermemory 701 and supplied to the high speed playback unit 730.

[0525] The high speed playback unit 730 is a means for reading from thebuffer memories 701 and 702 the waveform values corresponding to therespective pulses.

[0526] The read addresses ADR6 are changed in the range from “0” to“N-1” (where N is the number of waveforms to be read). Morespecifically, the high speed playback unit 730 generates read addressesADR6 during the period when each waveform value WD corresponding to acertain pulse is being written to one buffer memory, and repeatedlyreads over a number of times from the other buffer memory, all thewaveform values WD corresponding to the pulse before that pulse. At thistime, the generation of the read addresses ADR6 is controlled so thatall of the waveform values WD corresponding to one pulse are read outnormally within one fixed period. The period for reading all of thewaveform values for one pulse is changed to correspond to the level ofthe spectrum to be detected, with a change to T when a basic wavespectrum is detected, a change to 2 T for a second harmonic spectrum, achange to 3 T for a third harmonic spectrum, and so on. Moreover, thehigh speed playback unit 730 has an internal interpolator whichinterpolates the waveform values WI read from the buffer memory 701 or702, and outputs this as a waveform value of a predetermined samplingfrequency m/T (m is a predetermined integer).

[0527] A band pass filter 750 is a filter having a central frequency ofa predetermined value 1/T. A sine wave generator 740 is a variablefrequency waveform generator and comes under control of themicro-computer 606. It sequentially outputs respective sign waves ofperiods T, 2 T, 3 T, 4 T, 5 T and 6 T corresponding to the spectrumlevel to be detected. A spectrum detection unit 760 detects respectivepulse amplitudes H 1 to H 6 of each spectrum of the pulse wave, on thebasis of the output signal level from the band pass filter 750, anddetects the respective spectrum phases θ₁ to θ₆ on the basis of thedifference between the phase of the band pass filter 750 output signaland the phase of the sine wave output by the sine wave generator 740.

[0528] Chapter 5-1-2: Operation of the Analyzer (i)

[0529] The following is a description of the operation of the presentembodiment shown in FIGS. 46, 50 and 51.

[0530] Initially, on input of a frequency analysis start command fromthe input unit 602, a waveform collection directive START is outputtedby the micro-computer 606, and the waveform address counter 511 and thepeak address counter 523 the inside the waveform sampling memory 604 arereset.

[0531] (1) Waveform Division

[0532] As a result, the waveform address counter 511 starts counting thesampling clock f, and the waveform sampling memory 604 carries out in asimilar manner of the waveform section 412 explained at the index(a)-(1) in Chapter 4-2-2.

[0533] In other words, the waveform values W output in this way aresupplied sequentially to the waveform memory 503, and written to amemory area designated by the waveform address ADR1 at that time point P1 to P 3 .

[0534] In this analyzer, when the STRK is above a predetermined value,or more specifically, when the STRK is considered sufficiently close tocorrespond to that for the rising portion of the pulse wave (STRKM inFIG. 48), then the micro-computer 606 reads the waveform address for theminimum value stroke start point (STRKM start point P 6 in FIG. 48) fromthe peak information memory 525, and writes this to the internal shiftregister. The subsequent operations for when the peak points P3, P 4etc. are detected, are carried out in a similar manner.

[0535] (2) Wave Shape Transfer

[0536] In parallel with the above operation, the micro-computer 606successively reads the waveform values from the waveform memory 503inside the waveform sampling memory 604, and transfers these to thefrequency analyzing unit 605 as waveform data WD. The operation isdescribed below with reference to FIGS. 52 and 53.

[0537] As shown in FIG. 53, the select signal S11 is changedsynchronously with the clock phase, and the waveform memory 503synchronously, carries out a mode switching between the write mode andread mode.

[0538] In FIG. 52, when the waveform value of the pulse wave Wn of onepulse portion corresponding to a certain pulsation, is inputted to thewaveform memory 503, then at first the null cross detection signal Z isgenerated at the time point of input of the initial minimum value of thepulse wave corresponding to the pulse. That waveform address ADR1=A 0 iswritten to the peak information memory 525 (see FIG. 53). After this, oninput of the maximum value (address Al) into the waveform samplingmemory 604, again a null cross detection signal Z is generated (see FIG.53). When the stroke between the maximum value and the immediatelypreceding minimum value (address A 0 ) is above a predetermined value,the address A 0 of the minimum value is written to the shift resistor(not shown in the figure) inside the micro-computer 606. The waveformaddress written in this way, is then outputted from the shift resistorwith a delay equivalent to two pulsations, and fetched to themicro-computer 606 as the initial address of the waveform value WI ofthe one pulse portion to be transferred to the frequency analyzing unit605. That is to say, in FIG. 52, on writing the address Wn of themaximum value of the pulse wave WN corresponding to the certainpulsation, into the shift register, the starting address of the pulsewave Wn−2 read into the same shift resistor two pulses earlier (addressof the first maximum value), is outputted from the shift register, anddetected by the micro-computer 606.

[0539] At this time point, the micro-computer 606 refers to the contentsof the shift register and obtains the difference amount, from thewaveform address for the first minimum value of the pulse wave Wn−2until the address of the first minimum value of the next pulse wave Wn−1. That is to say the number N of waveform values included in the pulsewave Wn−1 of the single pulse portion is obtained. This is thenoutputted together with the synchronizing signal SYNC to the frequencyanalyzing unit 605. Moreover, the internal connection conditions of thedistributor 721, selector 711 and 712, and selector 721 are changed, forexample to the solid line conditions in FIG. 51, by changing the selectsignal S12 which is synchronized with the synchronizing signal SYNC.

[0540] Subsequently, the micro-computer 606 successively increases theread address ADR4 from the waveform address of the first minimum valueof the pulse wave Wn−2 , and supplies this to the waveform memory 503 byway of the selector 512. Here the read address ADR4 is changed at afaster speed (for example two times the speed) than is the write addressADR1. This is so that all the waveform values corresponding to the pulsewave Wn−2 which is prior to the pulse wave Wn−1 , can be read out beforethe maximum value of the pulse wave Wn+1 of the pulse after the pulsewave Wn is input to the waveform sampling memory 604. In parallel withthe storage of the pulse wave Wn in the waveform memory 503, themicro-computer 606 reads the waveform value WD for the pulse wave Wn−2two pulses prior, from the waveform memory 503, and transfers thesevalues to the frequency analyzing unit 605, and successively suppliesthe values to the buffer memory 701 by way of the distributor 721. Thewrite address ADR5 is successively increased from “0” to “N−1”,synchronously while the waveform values WD are successively supplied tothe buffer memory 701, and these write addresses ADR5 are supplied tothe buffer memory 701 by way of the selector 711. As a result, therespective waveform values WD corresponding to the pulse wave Wn−2 , arestored in the respective storage areas for the addresses “0” to “N−1”,in the buffer memory 701.

[0541] (3) High Speed Playback

[0542] In parallel with the above operation, the high speed playbackunit 730 outputs the read addresses ADR6, and supplies these to thebuffer memory 702 by way of the selector 712.

[0543] As a result, the respective waveform values WD corresponding tothe pulse wave Wn−3 one pulse prior to the pulse wave Wn−2 are read outfrom the buffer memory 702, and fetched to the high speed playback unit730 by way of the selector 722.

[0544] Here, the respective waveform values WD corresponding to thepulse wave Wn−3 inside the buffer memory 702, are repeatedly read over aplurality of cycles at a higher speed than the speed at which therespective waveform values corresponding to the pulse wave Wn−2 arestored in the buffer memory 701. At this time, the incrementing speed ofthe read address ADR6 is controlled so that the waveform values WD1corresponding to the pulse wave Wn−3 are all read out within a specifiedperiod T. That is to say, the high speed playback unit 730 incrementsthe read address ADR6 at a higher speed when the number of waveformvalues WD to be read from the buffer memory 702 has a large Ni value asshown in FIG. 54. On the other hand, in the case of a small N2 value asshown in FIG. 55, the read address ADR6 is incremented at a slowerspeed, so that the read address ADR6 changes the “0” to “N1−1” or “0” to“N2−1” segment within the specified period T. The waveform value WDsuccessively read out in this way is subject to an interpolationoperation in the high speed playback unit 730, and on attaining awaveform value WH of a specified sampling frequency m/T, is supplied tothe band pass filter 750.

[0545] (4) Spectrum Detector

[0546] The band pass filter 750 selects and passes a signal of frequency1/T from the time series data for the waveform WH, and supplies this tothe spectrum detection unit 760. On the other hand, the sine wavegenerator 740 generates a sine wave having a period T as shown in FIG.56, and supplies this to the spectrum detection unit 760. The spectrumdetection unit 760 detects the output signal level from the band passfilter 750 over several waves, and outputs a representative value as thebasic wave spectrum amplitude H 1 of the pulse wave Wn−3 . It alsodetects the phase difference between the output signal phase of the bandpass filter 750, and the output sine wave phase from the sine wavegenerator 740 over several waves, and outputs the representative valueas the basic wave spectrum phase q 1 for the pulse wave Wn−3 . Fromthese respective representatives values, are calculated for example theoutput signal level corresponding to the respective waves immediatelybefore output of the basic wave spectrum, and the mean movement value ofthe phase difference.

[0547] Next, the high speed playback unit 730 sets the incrementingspeed of the read address ADR6 to ½ in the case of basic wave spectrumdetection, so as to read all of the waveform values for the pulse waveWn−3 within the specified period 2 T. It also repeatedly reads out thewaveform values WH corresponding to the pulse wave Wn−3 , and suppliesthese to the band pass filter 750 (see FIG. 56). Then a signal offrequency 1/T, in the time scale data constituting the waveform valueWH, that is to say the signal corresponding to the second harmonic ofthe pulse wave Wn−3 is passed by the band pass filter 750, and suppliedto the spectrum detection unit 760. As a result the amplitude H 2 of thesecond harmonic spectrum of the pulse wave Wn−3 , is detected by thespectrum detection unit 760, and is outputted.

[0548] On the other hand, the sine wave generator 740 generates a sinewave having a period 2 T, and supplies this to the spectrum detectionunit 760 (see FIG. 56). As a result, the phase q 2 of the basic wavespectrum of the pulse wave Wn−3 is outputted by the spectrum detectionunit 760.

[0549] After this, in the case of the basic wave spectrum, the incrementspeed of the read address ADR6 is successively changed as ⅓, ¼, ⅕, ⅙.The period of the sine wave generated by the sine wave generator 740 isalso successively changed in conformity as 3 T, 4 T, 5 T, 6 T, and anoperation similar to the above carried out. The amplitudes H 3 to H 6and phases q 3 to q 6 of the 3rd to 6th harmonic spectrums, are outputfrom the spectrum detection section 760. The respective spectrums forthe pulse wave Wn−3 obtained in this way are fetched by themicro-computer 606.

[0550] The micro-computer 606 then computes the frequency:$f = \frac{1}{N \cdot \tau}$

[0551] of the basic wave, using the number N of waveform values WDcorresponding to the pulse wave Wn−3 and the period τ of the clock Φ,and outputs this together with the above-mentioned spectrum, from theoutput section 603.

[0552] Subsequently, the pulse wave Wn+1 one pulsation after the pulsewave Wn, rises, and on input of the initial maximum value into thewaveform sampling memory 604, the micro-computer 606 generates asynchronized signal SYNC and outputs the number N of the waveform valuesWD included in the pulse wave Wn−2 . Furthermore, the select signal S12is inverted so that the internal connection conditions in thedistributor 721, selectors 711 and 712, and selector 721 become thoseshown by the broken line in FIG. 51. Moreover, in parallel with storageof the pulse wave Wn+1 in the waveform memory 503, the micro-computer606 reads from the waveform memory 503, the waveform values WD for thepulse wave Wn−1 two pulses prior, and transfers these to the frequencyanalyzing unit 605, and successively supplies them to the buffer memory702 by way of the distributor 721. On the other hand, in parallel withthis operation, the high speed playback unit 730 reads from the buffermemory 701, the respective waveform values WD corresponding to the pulsewave Wn−2 one pulsation prior to the pulse wave Wn−1 , and then outputsthese as waveform values WH after interpolation by the high speedplayback unit 730. A similar processing to that for pulse wave Wn−3 , isthen carried out on the waveform values WH corresponding to the pulsewave Wn−2 , and the spectrum obtained.

[0553] Subsequently, the successively arriving respective pulse wavesare processed in a similar manner to the above, and the spectrums forthe respective pulse waves are obtained in succession and are outputtedfrom the output unit 603, as waveform parameters corresponding to theindividual pulses.

[0554] Chapter 5-2: Pulse Wave Analyzer (ii)

[0555] In the analyzer (i) explained in Chapter 5-1, the waveform datastored in the waveform memory 503, was played backed as pulsations andthe pulse wave spectrum computed for each pulsation. In contrast tothis, with the present analyzer (ii), a technique is used such as thatproposed by the present inventor in Chapter 2. With this technique, thevalues for respective elements of the electrical model, modeled on thearterial system dynamics of an examinee, are obtained on the basis ofthe pulse waves obtained from the examinee, and the results used ascondition indicating parameters.

[0556] The Model considers four parameters of the factors deciding thebehavior of the human circulatory arterial system; namely the moment dueto the blood flow in the arterial system proximal section, the vascularresistance due to the blood viscosity in the proximal section, thecompliance of the blood vessels (viscous elasticity) at the proximalsection, and the vascular resistance at the distal section, and modelsthese four parameters as an electrical model. The details of the modelhave described in Chapter 2-1.

[0557] In the present analyzer (ii), the micro-computer 606 by way ofthe selector 722, successively writes to one of the buffer memories 701,702, the waveform data corresponding to the respective pulses, and readsfrom the other buffer memory which is not being written to, waveformdata corresponding to one pulse. It then simulates the operation of thefour parameter model at the time an electrical signal corresponding tothe pressure wave at the arterial beginning section is applied thereto,estimates the values for the various parameters of the electrical modelso as to output waveforms corresponding to the waveform data read fromthe buffer memory 701 or 702, and outputs the calculated results aswaveform parameters. The values for the various parameters in theelectrical model can be obtained through trial and error by changing thevalues for the parameters and repeating the simulation operation.However it is also possible to use the technique described in Chapter 2.Moreover, the dynamic circulatory parameters may be obtained from thedistortion of the pulse waveform described in Chapter 3.

[0558] Chapter 5-3: Variation of the Fifth Embodiment

[0559] The fifth embodiment is not limited to the above analyzers (i)and (ii). For example, a number of variations such as given below arealso possible.

[0560] Analyzer (iii)

[0561] In the above analyzer (i) described in Chapter 5-1, the frequencyanalysis of the pulse wave was carried out by hardware. However thepresent embodiment is not limited to this, and frequency analysis may becarried out with software executed by the micro-computer 606.Furthermore frequency analysis methods such as DFT (Discrete FourierTransform), FFT (Fast Fourier Transform) and the like may be suitable.

[0562] Analyzer (iv)

[0563] In the above respective Analyzers (i) and (ii) described inChapter 5-1 and 5-2, the waveform parameters corresponding to therespective pulsations were outputted in real time as they were eachobtained. However the output method for the waveform parameters is notlimited to this method. For example the micro-computer 606 can computethe mean sum value of the waveform parameters for a predetermined numberof pulsations and output this. Moreover, the micro-computer 606 cancalculate the mean sum value of the waveform parameters of thepredetermined number of previous pulsations, that is to say, the meanmovement value of the waveform parameters, and output this in real time.

[0564] Analyzer (v)

[0565] In Chapter 5-1 and 5-2, the above respective analyzers (i) and(ii) for carrying out analysis of the radial pulse has been described.However the object of analysis of the present invention is not limitedto only the radial pulse. For example it may also be applicable tofingertip pulse waves etc. and other types of pulse waves.

[0566] Analyzer (vi)

[0567] Many parameters apart from those given in the respective examplescan be considered as waveform parameters of the pulse wave. When thepulse wave analyzer according to the present invention is used fordiagnosis, the waveform parameters can be changed to obtain thosesuitable for the diagnosis. For example, in Chapter 4, the presentinventor proposed an apparatus for obtaining an examinee's stress levelbased on the amplitude and phase of the peak points appearing in thepulse wave. With the apparatus according to the above embodiment,information related to the peak points can be obtained from the pulsewaves corresponding to each pulse, and used for evaluation of stresslevels.

[0568] In the present invention, the living body refers to the body ofthe examinee to be subjected to diagnosis or analysis, but the livingbody is not necessarily limited only to a human body. The basicprinciple outlined in the present invention should be equally applicableto animal bodies.

[0569] Furthermore, the present invention is not limited by theembodiments presented in Chapter 1 to Chapter 5. Various othermodifications or applications are possible within the principle ofdiagnosis based on detailed analyses of pulse waveforms.

[0570] While the invention has been described in conjunction withseveral specific embodiments, it is evident to those skilled in the artthat many further alternatives, modifications and variations will beapparent in light of the foregoing description. Thus, the inventiondescribed herein is intended to embrace all such alternatives,modifications, applications and variations as may fall within the spiritand scope of the appended claims.

What is claimed is:
 1. A pulse wave analyzing apparatus, comprising:waveform storage means for successively storing sequential data of pulsewaves of a living body according to a predetermined writing speed,playback means for dividing said sequential data into sequential dataeach corresponding to one pulse, and reading each of the dividedsequential data from said waveform storage means, and analyzing meansfor computing waveform parameters for pulse waves corresponding to eachpulse, based on sequential data corresponding to each pulse and readfrom said playback means.
 2. The pulse wave analyzing apparatus of claim1, wherein said analyzing means computes the spectrum of said sequentialdata, and outputs the sequential data spectrum as said waveformparameter.
 3. The pulse wave analyzing apparatus of claim 2, whereinsaid playback means repeatedly reads out said sequential data overseveral times at a read out speed higher than said writing speed.
 4. Thepulse wave analyzing apparatus of claim 3, wherein said playback meansreads out said sequential data for one pulsation from said waveformstorage means at a speed proportional to the data length thereof, andsaid analyzing means detects the spectrum of the frequency of oneinteger component of the read out period of said sequential datacorresponding to one pulse.
 5. The pulse wave analyzing apparatus ofclaim 4, wherein said playback means successively changes the readoutspeed to correspond to a level of the respective spectrums to bedetected, and said analyzing means detects for each change, the spectrumof a fixed frequency of one integer component of the read out period ofsaid sequential data corresponding to one pulse.
 6. The pulse waveanalyzing apparatus of claim 2, wherein said apparatus is provided witha sine wave generating means for generating and outputting a sine wavesignal having a frequency of one integer component of the read outperiod of the sequential data corresponding to one pulse, and saidanalyzing means detects the phase of the sequential data spectrum on thebasis of said sign wave signal.
 7. The pulse wave analyzing apparatus ofclaim 1, wherein said analyzing means (1) utilizes an electrical modelsimulating the arterial system from the proximal section to the distalsection of a living body, (2) enters electrical signals representing thepressure waveforms at the proximal section into said model; (3) computesthe values of the elements of said model so as to duplicate the waveformcorresponding to sequential data read from said playback means; and (4)outputs these computed results as said waveform parameters.
 8. The pulsewave analyzing apparatus of claim 7, wherein said electrical modelcomprises: (i) a first resistor simulating vascular resistance due toblood flow viscosity in said proximal section of said arterial system;(ii) an inductor simulating blood flow momentum in said proximal sectionof said arterial system; (iii) a capacitor simulating vascularelasticity in said proximal section of said arterial system; and (iv) asecond resistor simulating vascular resistance due to blood flowviscosity in said distal section of said electrical circuit; and aseries circuit with said first resistor and said inductor in series, anda parallel circuit with said capacitor and said second resistor inparallel, are successively arranged in series between a pair of inputterminals of said four parameter mode.
 9. The pulse wave analyzingapparatus of claim 1, wherein said analyzing means comprises: distortioncomputing means for computing a waveform distortion factor correspondingto each pulse on the basis of sequential data corresponding to eachpulse; and outputting means for outputting circulatory dynamicparameters on the basis of the computed waveform distortion factor. 10.The pulse wave analyzing apparatus of claim 1, wherein said analyzingmeans outputs an amplitude value and phase value at the peak point of apulse wave for each pulse.
 11. The pulse wave analyzing apparatus ofclaim 1, wherein said apparatus is provided with a reading means forreading out sequential data from a storage media.
 12. The pulse waveanalyzing apparatus of claim 1, further comprising a non-invasive pulsewave detecting means for detecting the pulse wave and obtaining thesequential data.
 13. The pulse wave analyzing apparatus of claim 1,wherein said analyzing means computes and outputs the sum mean value ofthe waveform parameters corresponding to each pulse for predeterminedpulse number units.
 14. The pulse wave analyzing apparatus of claim 1,wherein said analyzing means computes and outputs a mean movement valueof the waveform parameters corresponding to said each pulse.
 15. Thepulse wave analyzing apparatus of claim 1, wherein said apparatus isprovided with writing means for writing said circulatory dynamicparameters into a storage media.
 16. The pulse wave analyzing apparatusof claim 1, wherein said living body is a living human body.
 17. Adiagnostic apparatus, comprising: analyzer means for determiningwaveform parameters from information representing a pulse wave of aliving body; diagnostic means for performing a diagnosis of a conditionof said living body on the basis of said waveform parameters; memorymeans for sequentially storing both information relating to thecondition of said living body diagnosed by said diagnostic means, anddata relating to said diagnosis; and wherein said diagnostic meansoutputs information representing a degree of severity of a condition ofsaid living body.
 18. The diagnostic apparatus of claim 17, furthercomprising a means for outputting visual information corresponding tosaid degree of severity of the condition.
 19. The diagnostic apparatusof claim 18, wherein said visual information expresses said degree ofseverity of the condition with color.
 20. The diagnostic apparatus ofclaim 19, wherein said diagnostic means outputs information representinga degree of severity of a plurality of conditions of said living body,and wherein said means for outputting visual information determines acolor expressed in the visual information in accordance with acombination of information representing the degree of the severity ofeach condition.
 21. The diagnostic apparatus of claim 18, wherein saidvisual information expresses said degree of severity of the conditionwith shading.
 22. The diagnostic apparatus of claim 18, wherein saidvisual information expresses said degree of severity of the conditionwith a character.
 23. The diagnostic apparatus of claim 17, furthercomprising a means for outputting audio information corresponding tosaid degree of severity of the condition.
 24. The diagnostic apparatusof claim 23, wherein said audio information expresses said degree ofseverity of the condition with music.
 25. The diagnostic apparatus ofclaim 23, wherein said audio information expresses said degree ofseverity of the condition with a voice.
 26. A diagnostic apparatus,comprising: reading means for reading from a storage media, living bodyinformation containing waveform parameters representing a pulse waveobtained from a living body; and diagnostic means for performing adiagnosis on the basis of said living body information.
 27. Thediagnostic apparatus of claim 26, wherein said living body is a livinghuman body.
 28. The diagnostic apparatus of claim 26, wherein saidstorage media is a magnetic floppy disk.
 29. The diagnostic apparatus ofclaim 26, wherein said storage media is a magnetic optical disk.